Maintain api compatibility

* This update should maintain backwards compatibility with the deprecated `2011-02-01` API and the current API. Only currently deployed instances will work. Sites that meet one of the following criteria must use the new API. [New API documentation](http://docs.aws.amazon.com/cloudsearch/latest/developerguide/).  
    * adding the Lift plugin for the first time
    * deactivate the Lift plugin or 
    * clicking on (and confirming) `Reset Lift`
* A admin nag screen will pop up if a site is using the deprecated API (will continue to work).
* Fixed deactivation hook (it now works - it was not before)
* Added a confirm dialog for when user clicks on `Reset Lift`
* Added `post_excerpt` to the schema, which fixed message ` Field "post_excerpt" does not exist in domain configuration (near operation with index 1; document_id 1_1_1241)` that caused the documents to not be pushed to amazon.
* Adjusted schema to use types that matched new API docs (i.e. type `uint` is now `int`) [api documentation](http://docs.aws.amazon.com/cloudsearch/latest/developerguide/API_IntOptions.html)