YAG - Yet Another Gallery

You can find a first draft of an jm_gallery importer in the feature-jmgalleryimport branch on github. Here is a bunch of TODOs still left to do:

• Create Backend Administration Panel for importers
• Enable registration of arbitrary importers in this panel
• Put jm_gallery importer stuff into 3rd party extension
• Enable clearing of sys_registry table after import has finished
• Improve AJAX backend for importing (use different colors for import-progress, give some feedback, what is happening and when it is finished)
• Don't throw exception, if mapping has a jm_gallery element set which is no longer existing or if yag element has been deleted if a mapping has been set.
• Refactor jm_gallery importer class in such a way, that the complete import uses existing methods for importing categories, albums, images...
• Import meta data from images
• Check current version of jm_gallery and see, what has changed (we used an old version on kaktusteam, so perhaps database schema etc. might have changed...)