new header
add parents and test
Put the new commit header in the window
Preserve header collapsed state

Also fix adding parents to the header.
Clickable parents
Merge branch 'master' into header

Conflicts:
	Xit.xcodeproj/project.pbxproj
	Xit/XTFileViewController.m
	Xit/XTFileViewController.xib
XTWebViewController
Merge branch 'master' into header
Header formatting tweaks

- Remove whitespace around the message
- Increase line spacing
- Labels are non-selectable, with arrow cursor
- Rollover area for parent links is just the text
Don't resize header with split view
Adjust splitter when toggling header
Remove observers
Merge branch 'refs/heads/header'
Don't resize the header splitter when loading a commit
Fix the "not a repository" alert