Fix Loading Issue in lib/tree.js

This code fixes a bug whereby some tree elements will not yet
have loaded when the 'end' event is signalled.
Fix Loading Issue in lib/tree.js [Take Two]

... drrr.
Fix file path order bug.
Added test for improper commit sha
Merge remote-tracking branch 'refs/remotes/fatlotus/master'

Conflicts:
	vendor/libgit2
Updated convenience-commit's tree tests