Added support and tests for aggregation operations
Added a single pipeline entry job
Updated README.md with aggregation instructions
Removed code duplication
Reformated commit to align the patch
use JSON.serialize to handle issues with mongo document id's conversion to JSON
use JSON.serialize in command to sidestep issues with $ts conversion
add a sort order to single pipeline test to avoid non-deterministic result sorting.
Merge branch 'master' into better-aggregation-support

Conflicts:
	src/main/java/org/vertx/mods/MongoPersistor.java
merging in code from upstream
minor formatting fix
js formatting fix
js formatting fix - space after right bracket
Merge pull request #61 from thomsonreuters/better-aggregation-support

Better aggregation support