Refs #417. Changed container list to only have one heading link.
Refs #417. Added buttons for changing heading level.
Refs #417. Restructured the structured headings plugin to a more object-oriented style based off of the table plugin.
Refs #417. Removed tools for changing a heading level up or down and binded the functionality to the indent and outdent tools. Also, added basic fixStructuredHeadings function.
Refs #417. Updated the docs with new structured heading plugin features.
Refs #417. Added options for specifing the highest and lowest allowable heading level.
Merge branch 'master' into issue_417
Merge branch 'master' into issue_417
Refs #417. Fixed a number of small things such as coverage of all headings in some selectors and naming issues.
Merge branch 'master' into issue_417
Refs #417. Added tests for initializing the user interface and insertion of headings.
Refs #417. Added a large number of tests for structured heading indention and outdention. Fixed some other tests.
Refs #417. Made adjustements so that the test suite passes in IE7.
Merge pull request #417 from FriedRice/issue_417

Closes #417. UI improvements for the structured headings plugin