Merge pull request #13 from azakus/master

Fire tap on spacebar
README: add build status png
Update sidetable
test: add karma-ie-launcher
Set buttons for tap test
Fix up docs for PointerGestures

- Include grunt-contrib-yuidoc
- Discard grunt-contrib-clean
ignore node_modules, tools, and tests folders from yuidoc
remove stale yuidoc config file
test: refactor config file, add safari
test: use submodule tools
test: fix path to karma-common
Fix test race condition with DOMContentLoaded

Test tap could somtimes fire before the event handlers were added
Update CONTRIBUTING.md

Polymer/polymer#273
remove tools submodule
remove sidetable, use WeakMap