Added unit tests for tracer_db_facade.
Added tracer_db_facade implementation.
Added tracer_db configuration file.
Added some extra inline docs.
Added test for defaulting to $eq for db ops.

Added test to check that the tracer_db_facade defaults to the $eq
db operation if none is provided.
Added test for an unauthorized field.

Added test to ensure the tracer_db_facade will refuse to execute
a query targeting an unauthorized or invalid database field /
attribute.
Limit result count to MAX_RESULT_LIMIT.
Small jshint fixes.
Merge pull request #27 from Samnsparky/tracer_db_facade

Merge tracer_db_facade into master.