Add documentation to methods and variables

* Keeps phpstorm happy about variables
* preg_match was complaining about "!\%!" - replaced with '!\%!'
 - tested and both seem to work
Renable cache for list items
* Keep cache key short using crc32
* include matchon in the cache key
Merge pull request #138 from kehh/PROV-1007-ImporterFixes

PROV-1007 importer fixes