Fix BlameReport.setFirstVersion and use the correct argument order for assertEquals() in BlameOpTest.testBlameChangedByTwoCommits
cache only bucket trees
Set default max heap size to 2GB
refactoring internal to org.geogit.api.Node to use less memory
Make the BDB JE object database create a default je.properties configuration file
Several performance improvements targetted at the import large dataset use case

- New ObjectId.createNoClone(byte[]):ObjectId factory method used whenever the raw
hash byte array is obtained somehow else and its safe not to clone it.

- WorkingTree.insert(Iterator<Feature>, ...) calls in ObjectDatabase.putAll with a
transforming iterator that also has the side effect of adding the node to the
RevTreeBuilder whenever a feature is consumed.

- RevFeature and RevFeatureType maintain the original FeatureType attribute order
Use an intermediate byte buffer in JEObjectDatabase.putAll()

This intermediate byte buffer reduces memory consumption by avoiding
to clone multiple small buffers. and batch inserts as many blobs
as fit in the buffer in ObjectId order to ease the job of the database
when dealing with the btree.
set RevTreeBuilder default normalization threshold to 1M.
fixed issue in FeatureDiff class. Changes in feature types where not reported depending on how the existing fields were modified
Fixed issue with mixed feature types. For features not using the default FT, nodes had the default metadataId.
Revert "Use an intermediate byte buffer in JEObjectDatabase.putAll()"

This reverts commit 0ecf797a298553677cde5c64cb63a154ed2af65d.
Reason being that the buffer doesn't expand properly upon features that result
in a large encoded representation and the buffer can be overrun.
remove inexplicable code from test case
merge branch issue_93
fix RevertOpTest.testRevertWithoutCommit