add LZW compression to MongoObjectDatabase
added bulk putAll

Reduces import of wsa_rivers from 327 to 176 seconds
Added paralellization to mongo objectdb putAll

reduces import of wsa_rivers from 176 seconds to 73
Upgrade mongo-java-driver from 2.12.1 to 2.12.2
Merge remote-tracking branch 'groldan/mongo_improvements'
A couple fixes to JEGraphDatabase that prevented pushing from sparse clones.

map(ObjectId, ObjectId) was throwing an error if the "mapped" object id
didn't exist, instead of creating a new one.

ObjectIdBinding.entryToObject() was returning null instead of ObjectId.NULL
leading to an NPE's when NodeData.mappedTo was not expected to be null.
Merge branch 'master' of https://github.com/boundlessgeo/GeoGit
Fix bug in PushOp. It was updating local remote refs without the remotes prefix.
Add transparent gzip encoding to web-api request and responses
Merge pull request #770 from groldan/remotes_gzip_encoding

Add transparent gzip encoding to web-api request and responses
upgrade osmosis from 0.43-RELEASE to 0.43.1
Change BDBJEPointCache to store ordinates as int instead of double.

the osmosis OSM library treats node latitude and longitude
values as primitive ints instead of doubles, converting them
to double where necessary with a fixed precision of 7 decimals.
Let BDBJEPointCache use the same helper class to reduce the db
size.
Extract interfaces for all RevObject implementations

All RevObjects implementations but RevTree were concrete
classes instead of interfaces. This refactoring introduces
interfaces RevCommit, RevFeature, RevFeatureType, and RevTag,
and their default implementations RevCommitImpl, etc., making
the repository object model homogeneously defined by interfaces
instead of a mixin of interfaces and concrete classes, hence
allowing for alternate implementions, as may come from
optimizations of storage backends.