win msvs: Make ordering of sources in subdirs match gyp order

Sources in a given directory matched before, this makes folder order
match the gyp order also.

(collections.OrderedDict is py2.7; I'm not sure if that's a problem?)

R=mark@chromium.org, thakis@chromium.org
BUG=326030

Review URL: https://codereview.chromium.org/113053003

git-svn-id: http://gyp.googlecode.com/svn/trunk@1812 78cadc50-ecff-11dd-a971-7dbc132099af