Repeatable group and tinyMCE updates

Changes:
- Impetus behind changes was upgrading to WP 3.9 (which uses tinyMCE 4.0) and needing sortable repeatable groups that contained wysiwyg and radio inputs.

Issues I believe these changes address:
- #600
- #579
- #525 (sans the color picker)

cleanRow method:
- value attribute on radio and checkbox inputs not cleared so that they can have a value to submit
- Reworked wysiwyg code to work with WP 3.9 (which uses tinyMCE 4)
- Reset the tabs for the wysiwyg to have visual mode active
- update iterator value within $self.html (updates it in classes, ids, names)
- clear the style attribute on any textarea element within $self

afterRowInsert method:
- Updated tinymce.init call method parameter to work with tinyMCE 4
- Added Quick Tag initialization

updateNameAttr method:
- Added radix parameter value (10) to parseInt

emptyValue method:
- Added radio and checkbox input types to the jQuery selector so they won't have their value attribute cleared

addGroupRow method:
- Added radix parameter value (10) to parseInt

addAjaxRow method:
- Added radix parameter value (10) to parseInt

removeGroupRow method:
- MAJOR CHANGE. Instead of looping through all next groups and updating field names, loop through all remaining groups and shift the group field values up to the previous group. After this is done on the last group's values, remove the last group.
- Piggy-backs on the shiftRows event handler (slight hack used to add empty div with sortable classes used to trigger the upward shift)
- Shifting the field values up keeps all of the event handlers (such as the wysiwyg tabs) working correctly

shiftRows method:
- Added logic and functionality to enable 'radio' input type to be shifted to another group
- Added logic and functionality to enable wysiwyg values to be shifted to another group