change some forgotten URLs in licensing headers
i18n: mark catalogs for el (Greek), hy (Armenian), mk (Macedonian), and ta (Tamil) as fuzzy so they won't be compiled automatically.

Even before this change we did not ship '.mo' files for these languages.
remove JavaScript "test" files (were not executed years, probably broken anyway)
rename internal ID for built-in comments engine to get rid of all internal references to "mediacore".

Please note that this commit requires a DB migration.
rename classes and files containing the old 'mediacore' name
rename DB settings containing the 'mediacore' name.

Please note that this commit requires a DB migration.
rename setuptools egg to MediaDrop
fix wrong comment in PluginManager (plugin activation was added in MediaCore CE 0.10)
refactor plugin loading in PluginManager so we can support loading plugins from multiple entry points
switch main entry point from "mediacore.plugin" to "mediadrop.plugin" (but also add some compatibility code so old plugins can still be loaded)
MediaDropPermissionSystem now uses the key "mediadrop.perm" in the wsgi environ (instead of "mediacore.perm")
change JavaScript namespace from "window.mediacore" to "window.mediadrop"
add the ability to configure the file serving alias in nginx (currently by default "__mediacore_serve__")
change internal file serving alias for nginx from "__mediacore_serve__" to "__mediadrop_serve"
rename helper function "mediacore_version()" to "mediadrop_version()"
fix bad reference to 'format_number' in mediacore.lib.i18n.__all__
change package name from mediacore to mediadrop and eliminate some of the remaining references to MediaCore. Also the gettext domain is changed to mediadrop.
This results in a huge changeset but the idea is that nothing really changes for users who don't use any plugins.

This commit should eliminate all internal references to mediacore and there is very little left in the templates/JS code.
add compatibility package for "mediacore" so hopefully most plugins will continue working until we fixed all of them.