Merge pull request #47 from abeisgreat/master

Fixes #46
Fix AnnotationList bug resulting in incorrect markers in some cases.
Add "entity" support so you can add things like images.
Merge branch 'master' of github.com:firebase/firepad
Bunch of improvements for entity / img support.

* Add export / import.
* Fix issue where entity attributes were being copied to other characters.
* Fix issue where consecutive identical entities were being collapsed into one.
* Misc. refactoring / cleanup.
Force CodeMirror refresh after adding entities.
Batch line marking operations to improve performance (especially on initial load).

Also, fix parseHtml() tests I broke with image support.
Provide an "entityHandle" to the entity render function that lets it later find the entity, remove it, or replace it.
Fixed EntityManager exportToElement
Changed args order for EntityManager tryRenderToElement_ to make entityHandle non required
Updated build
Fixed RTCM createEntityHandle_ support for remove with char at index 0
Update firepad.js
Enable self cursor tracking (basics for live toolbar update)
Build
Fix apply context/args
Build
Fix #58 Exception after removing entity.
Merge pull request #57 from LiveMinutes/fix_cursor

Enable self cursor tracking (basics for live toolbar update)
Add Google Group link to README