Initial commit for the HierarchyBuilder extension.

New extension HierarchyBuilder for building and managing hierarchical
representations of wiki pages.

Generated a correct HierarchyBuilder.i18n.php file for backwards
compatability.

Removed legacy .svn directories.

Removed unused css themes.

Updated the authors credits to include links to the author pages.

Added a url to the extension credits to link to the HierarchyBuilder
extension page.

Corrected the version number to be version 1.0.

Renamed the parser functions "children", "parent", and "sectionNumber" to
be "hierarchyChildren", "hierarchyParent", and "hierarchySectionNumber".

Corrected the i18n messages to use full stops and proper capitalization.

Refactored all HierarchyBuilder.php so that classes are contained within
their own files and are autoloaded by HierarchyBuilder.php

Renamed the EditHierarchy class as HierarchyFormInput and renamed
SelectFromHierarchy as HierarchySelectFormInput.

Updated RTL handling.

Updated DOxygen documentation to reflect the correct parser function
names.

Change-Id: Ib28c03e9d6e0bc65a33dd544809003cbc35c2796