Make sure the scrollbar is showed at the bottom

Wrap all diffs in one table, so we can set 'overflow' on the whole area.
Merge branch 'feature/keep-scrollbar-at-bottom' into t

Conflicts:
	libgitg/resources/diff-view.css
	libgitg/resources/diff-view.js
Make sure the scrollbar is showed at the bottom

Wrap all diffs in one table, so we can set 'overflow' on the whole area.
Merge branch 'feature/keep-scrollbar-at-bottom' into t

Conflicts:
	libgitg/resources/diff-view.css
	libgitg/resources/diff-view.js
Make sure the scrollbar is showed at the bottom

Wrap all diffs in one table, so we can set 'overflow' on the whole area.
Merge branch 'feature/keep-scrollbar-at-bottom' into t

Conflicts:
	libgitg/resources/diff-view.css
	libgitg/resources/diff-view.js
Render message body separately

So that we can have more control over both the 'subject' and the
'message body'.
Merge branch 'feature/separate-commit-message' into t

Conflicts:
	libgitg/resources/diff-view.css
	libgitg/resources/diff-view.html
Show message body with the commit diff

Also make it scroll with the commit diff.