Add opacity support for groups
One forEach
Optimize SVG renderer
Externalize rounding function

It's actually a bit faster this way
Fix test: The new rounder doesn't return trailing zeros
Headless Qunit
Fix XHR errors

Need to open the request before setting attributes.
Merge pull request #106 from DieBuche/FurtherOptim

Further optims
Merge pull request #108 from DieBuche/headlessQUnit

Headless Qunit
updated gitignore
added internal reference to Two in order to fix noConflict issues
took `round` logic from svg and extrapolated to Two.Utils for use in other renderers
updated readme
Only bubble up _update if it is called by getBoundingRect.
Merge pull request #109 from DieBuche/Update

Only bubble up _update if it is called by getBoundingRect.
Merge branch 'opacityForGroup' of https://github.com/DieBuche/two.js into dev
groups now contain opacity
Merge branch 'dev' of https://github.com/jonobr1/two.js into dev
updated readme
made flagOpacity boolean by default