setup: add known internal paths for test input data and regression exe (

#7)

* feature: manage internal bin path as source of release and rebuilt exes
* refactor get_exes and build_exes to class with interface
* refactor targets to class with interface
* add test context object for updating devtools and providing target dict based on shared bins
* restore expected download temp dir
* refactor: manage internal bin path as source of release and rebuilt exes
* fix Simulation object to cache target dict
* refactor: manage internal bin path as source of release and rebuilt exes

.gitignore

@@ -132,6 +132,6 @@ dmypy.json
 .idea/
 
 # downloaded exe
-modflow_devtools/bin
-modflow_devtools/utilities/temp
+bin/
+modflow_devtools/utilities/temp/
 

.gitmodules

@@ -0,0 +1,12 @@
+[submodule "data/model/modflow6-testmodels"]
+	path = data/model/modflow6-testmodels
+	url = ../modflow6-testmodels.git
+	branch = master
+[submodule "data/model/modflow6-largetestmodels"]
+	path = data/model/modflow6-largetestmodels
+	url = ../modflow6-largetestmodels.git
+	branch = master
+[submodule "data/example/modflow6-examples"]
+	path = data/example/modflow6-examples
+	url = ../modflow6-examples.git
+	branch = master

data/reference/ibc01_ibound.ref

@@ -0,0 +1,20 @@
+         0         0         0         0         0         1         1         2         1         1         0         0         0         0         0
+         0         0         0         0         2         1         1         2         1         1         1         2         0         0         0
+         0         0         0         2         1         1         1         1         1         1         1         1         0         0         0
+         0         0         0         1         1         1         1         1         1         1         1         2         0         0         0
+         0         0         2         1         1         1         1         1         1         1         1         1         2         0         0
+         0         0         1         1         1         1         1         1         1         1         1         1         1         2         0
+         0         2         1         1         1         1         1         1         1         1         1         1         1         1         0
+         0         1         1         1         1         1         1         1         1         1         1         1         1         1         0
+         1         1         1         1         1         1         1         1         1         1         1         1         1         1         1
+         1         1         1         1         1         1         1         1         1         1         1         1         1         1         1
+         1         1         1         1         1         1         1         1         1         1         1         1         1         1         1
+         0         1         1         1         1         1         1         1         1         1         1         1         1         1         1
+         0         1         1         1         1         1         1         1         1         1         1         1         1         1         0
+         0         2         1         1         1         1         1         1         1         1         1         1         1         2         0
+         0         0         1         1         1         1         1         1         1         1         1         1         1         0         0
+         0         0         2         1         1         1         1         1         1         1         1         1         2         0         0
+         0         0         0         1         1         1         1         1         1         1         1         1         2         0         0
+         0         0         0         2         1         1         1         1         1         1         1         2         0         0         0
+         0         0         0         0         0         0         2         1         1         1         0         0         0         0         0
+         0         0         0         0         0         0         0         1         1         0         0         0         0         0         0

data/reference/ibc03_dstart1.ref

@@ -0,0 +1,10 @@
+ 22.659 22.314 21.659 21.246 21.045 21.045 21.246 21.659 22.314 22.659
+ 21.622 21.127 20.711 20.419 20.270 20.270 20.419 20.711 21.127 21.622
+ 20.114 19.628 19.267 19.026 18.905 18.905 19.026 19.267 19.628 20.114
+ 18.047 17.619 17.327 17.142 17.051 17.051 17.142 17.327 17.619 18.047
+ 15.116 15.030 14.930 14.850 14.807 14.807 14.850 14.930 15.030 15.116
+ 12.470 12.443 12.404 12.368 12.346 12.346 12.368 12.404 12.443 12.470
+  9.870  9.845  9.805  9.766  9.742  9.742  9.766  9.805  9.845  9.870
+  7.297  7.235  7.133  7.029  6.970  6.970  7.029  7.133  7.235  7.297
+  4.891  4.709  4.383  4.017  3.864  3.864  4.017  4.383  4.709  4.891
+  3.135  2.680  1.696  0.000  0.000  0.000  0.000  1.696  2.680  3.135

data/reference/ibc03_dstart3.ref

@@ -0,0 +1,10 @@
+ 13.294 13.295 13.296 13.297 13.298 13.298 13.297 13.296 13.295 13.294
+ 13.270 13.275 13.278 13.279 13.280 13.280 13.279 13.278 13.275 13.270
+ 13.214 13.218 13.221 13.223 13.224 13.224 13.223 13.221 13.218 13.214
+ 13.129 13.132 13.134 13.136 13.136 13.136 13.136 13.134 13.132 13.129
+ 13.024 13.026 13.027 13.028 13.028 13.028 13.028 13.027 13.026 13.024
+ 12.911 12.911 12.911 12.910 12.910 12.910 12.910 12.911 12.911 12.911
+ 12.801 12.799 12.797 12.796 12.796 12.796 12.796 12.797 12.799 12.801
+ 12.707 12.703 12.700 12.698 12.697 12.697 12.698 12.700 12.703 12.707
+ 12.640 12.636 12.632 12.630 12.628 12.628 12.630 12.632 12.636 12.640
+ 12.611 12.610 12.608 12.606 12.605 12.605 12.606 12.608 12.610 12.611