Add tilebuilder to gitignore
Add tilebuilder to gitignore

BUG=skia:
R=jcgregorio@google.com, bensong@google.com

Author: kelvinly@google.com

Review URL: https://codereview.chromium.org/384863003

Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot