finished unittests for plugin disks
finished unittests for plugin help
finished unittests for plugin language_selection
finished unittests for plugin logs
finished unittests for plugin network
finished unittests for plugin plugin_manager
finished unittests for plugin shutdown
finished unittests for plugin system_preferences
finished unittests for plugin user_manager
added english 'translations' to all plugins (by copying msgid to msgstr)
plugin plugin_manager: prevent browser from caching repeatitive actions
plugin plugin_manager: add support for properties/volume visibility
plugins: moved message handling to central header file (templates/header.cs)
splitted 'volume_props' into 'volume_rename' and 'volume_chpasswd'
volume_props: turned into a container for small property changes
renamed 'format_fs' to 'volume_format_fs'
moved inclusion of 'show_volume_[header|footer].cs' to central header file