Add git branch command.
Add git checkout command.
Add git push command.
Add git commit command.
Add merge support in git.
re-working how we include the sdk
More work on merge trees.
Merge branch 'master' into git_branch
minor fixes.
Add git pull command.
Add git conditions class.
expander icon tweaks
finished refactor of sdk code
merge to master
cleanups
Half-way through: dumb UI works, but underlying Dart is mostly disabled

...as a result, the toolbar and splitter show, but buttons don't do anything, and file treeview pane and edit pane are empty.
Highlight only when dropping is possible (fixed #303) and fixed persistant highlight issue (fixed #310)
Incorporated CL suggestions from ussuri
cleanup
implement rename