Move Foundation.framework to frameworks group.
Remove the PBGitSHA class and use the GTOID class from Objective-Git instead.
Remove unnecessary copying/passing by value of git_oid
Merge branch 'upstream' into feature/gtoid. Update GTOID branch with latest upstream changes.

Conflicts:
	Classes/git/PBGitCommit.h
	Classes/git/PBGitCommit.m
	Classes/git/PBGitHistoryGrapher.m
	Classes/git/PBGitRepository.m
	Classes/git/PBGitRevList.mm
	Classes/git/PBGitSHA.h
	Classes/git/PBGitSHA.m
Fix #310 - diff highlighter breaks on some strings

Strings like “constructor” occur as properties on JavaScript objects by default:

```
var x = new Object();
x[“constructor”] // Object
```
fixes #321: Word diff highlighting breaks for swapped phrases
Merge pull request #325 from muhqu/gitx-dev-issue/321

fixes #321: Word diff highlighting breaks for swapped phrases
#315 Generate lane colours on a HSB ring, much brighter and more saturated than the Solarized scheme
#315 Tone down the drop-shadow on ref labels

They still look a lot better than the solid outline, especially on Retina; so I’m hoping this helps with the visual weighting of the readability problem.
#315 lighter colours for ref labels
Merge remote-tracking branch 'refs/remotes/origin/master'
#315 Try bumping the font size of ref labels
Update README with OS X support info
Fix #318: need to use the branch name, not full ref path when calling lookUpBranchWithName
Fix #317: Reinstate ability to delete refs/remotes/*
Update release notes
Update release notes
Update build script to help prepare artefacts for publishing
Convert bytes hex to string in appcast template code
Tag builds during the publish stage