Releases for Snippets

Fixing issue where empty snippets could not be edited by admins

#2483417 - Expose Tokens widget to Snippets

• Issue #2036757 - Added snippet ctools content types as subtypes
• Issue #2280583 - Addressing Drupal coding standards
• Added views area handler plugin

Check for the admin_links variable in the theme to prevent notices in the theme file.

- Added backwards compatibility for older versions' snippet title setting
- Added placeholder text for empty snippets when user has administer or manage snippet permissions
- Added snippet.css file

1. Added code to disable loading of snippet if it is disabled
2. Wrapping title in check_plain
3. Wrapping content in check_markup
4. Disable delete button from inside form

While previewing content the preview was not functional as expected. Resolved this preview issue.

Major changes in terms of code architecture has been ported. Still the use is the same.
Changes are as follows,

1. Removed two snippet administrations links. Kept only one 'admin/snippet'
2. One can revise title as wel
3. Used ctools export-ui to archive goals

Fixed #1609408: Snippets not making entires for revisions on enabling or reverting a feature.
Issue was not able to create revision id for the snippets to maintain revisions.
Snippet machine name is now a mapping reference for a snippet and its revisions.