added help texts for all plugins
fixed 'encryption status' bug in 'volume_details'
improved rendering of 'volume_properties' and 'user_manager'
chmod root directory of mounted volumes to 0777 to avoid later permission problems for samba or WebDAV
moved log file reading from cryptobox/core/main to 'log' plugin
added unittests for volume_mount, volume_format_fs and volume_rename
replace "get help" links with a "help mode" displaying information for every form
added first drafts of help texts for volume_mount, volume_format and partition
replaced the word 'container' with 'volume' in english texts