Nicer style for the "long diff" message

Conflicts:
	MGScopeBar
Add diffstat info to the list of files in the commit view

Visual changes:
* Use a more structured table layout for the list of files.

Obj-C Code changes:
* Load the diffstat info with:
      $ git show --numstat -M --summary --pretty=raw $REV
  and then (as a 2nd, separate NSTask) load the full diff, with:
      $ git show --pretty=raw -M --no-color $REV
* A side-effect of this is that you now get a list of files changed in a
  merge commit, whereas it used to only show the commit message.

Javascript/HTML code changes:
* Get the commit view header info from the first task, so it should load
  quicker, especially for commits with really long diffs.
* Use the --numstat info (from the output of the first NSTask) to get the
  full list of files changed and the number of changed lines in each, and
  the --summary info to see if any files were created/deleted.
* Add a "prototype" of the file-list element in index.html, and then have the
  javascript extract then clone that, rather than building the elements
  totally in code.
* Add javascript functions to show/hide the lines added/removed details when
  the mouse hovers over the lines changed summary.

Conflicts:
	Classes/Controllers/PBWebHistoryController.m
	MGScopeBar
	html/views/history/history.css
	html/views/history/history.js
	html/views/history/index.html
Fix contextual menu for files in new filelist

Also, better handle filenames with spaces
Conflicts:
	MGScopeBar
Tweaked colors in new file list a bit

* Made the border color match the file diffs.
* Made the background color lighter and the text
  darker, so it's easier to read (and doesn't have
  the slight look of being disabled that it used
  to have).
* Changed the text shadow on the file names so it
  doesn't looks weird when overlapping a graph bar.
  In fact, now it helps readability in that case.
Conflicts:
	MGScopeBar