[manual] Mention CodeMirror.signal

Closes #1698
Revert "When pasting on Webkit, add a nonsense character to work around browser bug"

This reverts commit d59e2ae4e56b6279bbde82e5618e8013910c27b8.
[xml mode] Improved indentation for attributes and multi-line tags

Issue #1694
[tern addon] Fix bug in findDoc method causing docs to get added with name of 'undefined'

The name var was getting clobbered in the initial for-in loop, so the
second loop would never be entered.
Allow DOM events to be ignored by setting codemirrorIgnore

Issue #1681