bug fix laundry list

[tracyhenry]

finished a laundry list of things required/complained by people over past 18 months

• fixed multi-view zoom buttons overlap #121
• fixed pg native box/cube indexers have scaling issues #120
• fixed svg.getBBox() ignores transforms when static layer semantic zoom  #97
• fixed pushing predicate generation into backend (important security issue) #60 using a predicate validator
• added canvasId and layerId to optionalArgs when possible
• upon serving errors, close all pg connections so the next query can be run
• separated citus and native box code
• removed try/catch in getColumnNames() so errors can be caught higher up
• made the web embedding examples work with the updated APIs
• added down and stop option for run-kyrix.sh
• fixed run-kyrix.sh will hang if there is an error in starting up #129 with a 3-minute timeout
• added -h --help options to docker scripts (load-csv load-sql run-kyrix)
• provided project name to docker-compose commands, so the root directory name won't alter container names
• updated docker installation instructions (docker-compose requires v1.17.0+)
• arbitrary aggregation for heatmap SSVs