msvs: Fix rule dependencies for VS2013

This commit does two things to fix rules for VS2013:

* Don't exclude rule 'input' files (i.e. the files that will be used as
  'AdditionalDependencies' in the msbuild rule definition).
* Use a 'CustomBuild' element for 'AdditionalDependencies' files, instead of
  using 'None'.  This is similar to how the primary input of actions is added
  in '_AddMSBuildAction'.

Also, re-enable the test/rules-rebuild/gyptest-default.py test for VS2013.

BUG=gyp:465
R=scottmg@chromium.org

Review URL: https://codereview.chromium.org/699203003

git-svn-id: http://gyp.googlecode.com/svn/trunk@1997 78cadc50-ecff-11dd-a971-7dbc132099af