* Remove explicit declarations of class, id, style, and title from $allowedposttags
* Dynamicallly add global attributes to every tag for the 'post' context
* No longer calls wp_kses_array_lc() every time wp_kses() runs. Instead it runs once if CUSTOM_TAGS is true. Plugins directly passing a custom allowed_html array will no longer get the lc treatment. Keep an eye out for problems with this.
* wp_kses_data() and wp_filter_kses() pass current_filter() for the $allowed_html argument to wp_kses().
* wp_kses_allowed_html() handles being passed a filter name for a context. If the filter is not a recognized one it defaults to using $allowedtags as was done before for wp_kses_data() and wp_filter_kses().
* wp_kses_allowed_html() recognizes user_description and pre_user_description out of the box. For these it takes $allowedtags and inserts rel attribute support.
* wp_kses_allowed_html() allows plugins to override the return values for the default contexts and support arbitrary contexts via a wp_kses_allowed_html filter.
* wp_kses_hook() can now pass a string context for $allowed_html to the pre_kses filter. We might have to pass the result of wp_kses_allowed_html() instead if it turns out that plugins are digging in $allowed_html.
fixes#17977
see #20210
git-svn-id: https://develop.svn.wordpress.org/trunk@21790 602fd350-edb4-49c9-b593-d223f7449a82
0cef59e4c0