cups-browsed 2.1.1

Bug fix release, especially to fix the problem that cups-browsed sometimes gets stuck with 100% CPU.

• Do not use global HTTP connection to local CUPS
  cups-browsed used a simple HTTP connection to CUPS and preserved it in a global variable throughout its whole life. With the addition of multi-threading this caused race-conditions and especially cups-browsed getting stuck in a busy loop. Now we create separate HTTP connections each time we need one, to eliminate this problem (Ubuntu bugs #2049315, #2067918, and #2073504, CUPS Issue #879).
• Fix uninitialized make_model in create_queue()
  Initialized the buffer by putting a terminating zero to its beginning, also removed a wrong use of sizeof() (applying to pointer no to buffer, Issue #42).