The vs_files directory is used for VS 2015 builds and needs to be in
.gitignore, along with vs2013_files.

The naming convention for timestamps is changed and .gitignore needs to
be updated for that.

Finally, the .pylint.d directory keeps being created and should be
ignored.

Review URL: https://codereview.chromium.org/1667853004

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@298682 0039d316-1c4b-4281-b951-d872f2087c98