Send groups with errors in AsyncComponent, refs #160
Clear error groups on disconnect, refs #160
Document the error handling change in AsyncComponents, refs #160
Add group handling helpers to the error helper method, and add tests for it. Refs #160
ComponentLoader: guess component source language using filename extension
Merge pull request #161 from djdeath/component-language-guess

guess component source language using filename extension
Automatically rewritten for npm.