Added stripCloneAtts() method.
Renamed method to stripCloneAttrs()
Fixed false-negative attribute check bug.

The check now allows for "false" boolean attributes.
Test case for #219.
Return the clone
Built CS file
Merge branch 'master' into clone-attributes-fix
A more robust way to check if the model attribute exists

previously the clone attribute wouldn't get removed if set to `null` or
`undefined`.
Fixes record re-creation on DELETE that returns non-empty response.
Move destroyed check up to first line.
More descriptive 'unknown record' errors
Improve error log message when a model record isn't found
Can unbind to multiple events at once. For example,

    User.unbind("save update destroy", @callback)
Expose the classes in relation.coffee so that they can be extended.
Merge pull request #396 from jeremyhaile/improve_find_errors

Improve error log message when a model record isn't found
Merge pull request #376 from mbleigh/ajax-delete-recreation

Records are re-created on DELETE that returns non-empty response.
update github references
a few of the better bits (IMO) from pull request #346
Added stripCloneAtts() method.
Renamed method to stripCloneAttrs()