Use tools repo for mocha and chai

Zero install browser test runner
Merge pull request #275 from azakus/zero-install-test-runner

Use tools repo for mocha and chai
Wrap try/catch around canvas getContext webgl

- Firefox throws exceptions for unsupported graphics cards, which causes the tests to fail
Merge pull request #276 from azakus/firefox-webgl

Wrap try/catch around canvas getContext webgl
Fix issue with non identifier names
Merge pull request #279 from arv/fix-non-identifier-name

Fix issue with non identifier names
Add support for new Image
Merge pull request #280 from arv/new-image

Add support for new Image
Fix issue with canvas parameters
Merge pull request #284 from arv/webgl-fix

Fix issue with canvas parameters