Update the scripts for the snapshot of 37

- The svn repo string would be something like:
  ...branches/2062/path_suffix
  and I want only the branch number in this case.
  Updated git_submodule.py to support that case and use regexp
  instead to keep thing a bit simpler.
- .isolate are gyp files, moved the exception at the top
- Changed some inclusions/exclusions
- tools/ is now all excluded by default with exception instead
  of all included. We don't need most of it.

Change-Id: I6d0666d9af7fc6a0f3c4fe866adf2744f13f7c35
Reviewed-by: Andras Becsi <andras.becsi@digia.com>