Initializing Query.transaction to Transaction.NULL
Handling other types of Transaction
Throwing back exceptions during transaction
add no-op hook for when response is fully complete

this enables disabling profiling in the geodroid build for
streaming/lazy responses like feature JSON
Better handling of file groups.

Grouping files by base name when processing, fixes #42.
Merge pull request #43 from jdeolive/dirrepo-filegroup

Better handling of file groups.
Merge branch 'master' into geogit-android

Conflicts:
	format/geogit/src/main/java/org/jeo/geogit/GeoGitAppendCursor.java
	format/geogit/src/main/java/org/jeo/geogit/GeoGitCursor.java
	format/geogit/src/main/java/org/jeo/geogit/GeoGitDataset.java