Moved skeleton code to new Plugins location.
New info file format.
New info file extension.
Issue #1241192 and #1905312 by Peacog: Removed attributes to fix HTML validation.
Issue #1918116 by DuaelFr: Remove useless files[] directive from .info files.
Issue #1922536 by dmcmeans: Fixed Select none fails for jQuery 1.7.1.
Issue #1869082 by mikeker: Fixed Exposed operators excluded from secondary exposed form options.
By mikeker: Correctly handle hierarchical taxonomy filters when rewriting filter options.
Issue #1905418: Fixed description field for radios not shown.
Issue #1905312 by mikeker: Fixed XHTML validation issue.