Initial pass at Branch, Remote and Tag ops for web-api.

Currently supports list operations, will add more functionality to it as we need it.
Added changes to Branch, Remote and Tag web-api ops.

Changed responses to work with the geogit ui in salamati. Added listing of remote branches to branch op.
Initial implementation of FeatureDiffWeb.

Get the diff of a feature based off of two commits.
Updated FeatureDiff web-api implementation to return the appropriate information in the response.
Added initial implementation of commit graph interface for web-api.
Added page option to log and getCommitGraph through the web-api.
Updated Diff web-api version to return the objectId, changeType and geometry.
Initial pass at culling out features from diff by means of a bounding box.
Fixed a bug with building diff command in web-api.

Made a parseDouble function based off the already existing parseInt function to avoid running into a NPE.
Added typecast for Geometry in Diff response so that it uses the correct toString function.
Was using the wrong function to print geometry as a string.

Changed toString call to toText.
Fixed problem with passing null object id to FeatureDiffWeb.
Changed Diff Response so that it will get the geometry.

Currently GeogitSimpleFeature doesn't get the correct attribute for the geometry because of some issue with mapping types to indices.
Added javadocs for base web api classes.
Added comments to the web-api commands to build java-docs from.
Merge branch 'WebApiChangesRebased' from KelseyIshmael.