Returns 400 error for bad filters and missing columns in queries
Changes expected error code for query without geometry
Changes regex for missing columns and adds unit test to cover the error to status conversion
Merge pull request #189 from CartoDB/CDB-3000

Returns error 400 for queries with invalid columns or invalid cartocss rules/filters
Adds document about metrics being tracked
using literal expression for regexp
Extracts stats client to its own file/class so it can be used as stub when there is no configuration for statsd. That helps to remove some sanity checks to see if the stats client is created or not.
adds chronograph dependency to start tracking postgre queries in torque by wrapping callbacks to pg.query method. It will report to using statsd client
Removes profiling for cors.
Proxy all profiler calls so there is no need to keep checking for profiler existence.
CDB-3045 increment in statsd only supported formats
CDB-2570 introduces a method to check whether the cache buster must or must not invalidate the renderer: in case the cached buster and the requested buster are numeric and the requested one is bigger the renderer will be invalidated
CDB-3079 enforces postgres user in preparation script and changes travis config to use postgres 9.3, postgis 2.1 and mapnik 2.2.0
CDB-3079 testing with mapnik v2.1
CDB-3079 install mapnik and gdal before adding cartodb repositories
CDB-3079 coming back to initial travis config
CDB-3079 testing latest 0.7.x mapnik version
CDB-3079 testing mapnik 1.4.5 version
CDB-3079 testing mapnik 1.4.5 version + postgres travis config
CDB-3079 trying mapnik v2.1.0