refactored metabox + changed TrackableObjectAbstract required variables names
remove htmlpurifier as dependency
Metabox: implemented automatic meta fields detection by parsing DOM output of callback function
Metabox: minor inline documentation fix
cleaned UI List plugin + added back fallback inputs for PHP + fixed output buffer inplementation for templates
minor UI List JS fixes + added optimized scripts version
Metabox: fixed output buffer implementation to get meta fields from callback
fixed exception throwing with wrong namespace
fixes #36
added a couple of missing capabilites methods and missing inline docs
fixes #37