This change moves the code I added to git-cl to parse the results of the presubmit hooks into presubmit_support itself. It also removes a lot of the text-file parsing that is no longer necessary since everything is in process.

It also simplifies all of the PresubmitResult* objects and the way we're using output streams since we can assume more about how the callers are calling us.

Note that I uses PEP-8 style method names where I was adding entirely new classes (or rewriting existing classes completely) since per maruel@ he is trying to new that style for new code.

This change also contains two small changes to git_cl to fix bugs and restore the previous behavior of --force skipping the presubmit checks.

Review URL: http://codereview.chromium.org/6694009

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@78328 0039d316-1c4b-4281-b951-d872f2087c98