events: remove html tags from ical export, re #71
courses: remove html tags from locations, re #71
user: remove html tags from adress, fixes #71
events: strip more html tags, re #71
messages: detect utf-8 and convert it to valid charset, fixes #74
messages: enable reading_confirmations, re #72
Merge branch 'master' of github.com:studip/studip-rest.ip into studip-2.2
adjust changes from trunk