Added feature geometry diff. When the user selects a feature diff to view, a window will appear allowing them to switch between new or old versions of the feature's geometry. Story #772 reviewing
When the user adds a layer, the map will no longer zoom to its extent automatically.  Instead, a "Zoom to Layer" button has been added to the layer tree's context menu.
Improved the workflow for viewing feature diffs.
Added basic merge functionality to Salamati.
Merge branch 'mergeUI'

Conflicts:
	webapp/src/app/app.js
	webapp/src/gxp/script/plugins/DiffPanel.js
Added geometry to merge review.

Moved the diff geometry things from DiffPanel to GeoGitFeatureAttributeGrid since the two are tied together.
Added a function to GeoGitUtil to get the name of the attribute for geometry since it was duplicated in many places.
Merge commit '2032a63bcb100dc69f2c14439ded87e9ade3d373'

Conflicts:
	webapp/src/app/app.js
	webapp/src/gxp/script/GeoGitUtil.js