Initial support for SRV/TXT service discovery
CalDAV/CardDAV service discovery with SRV/TXT records

* Structural changes in the strings file (for translations)
Version bump to 0.6.7

* a few fixes for SRV service detection
* localization strings cleanup
* new policy for localization: translators are only mentioned on their own translation from now on
Merge branch 'master' of github.com:rfc2822/davdroid

Conflicts:
	res/values-hu/strings.xml