* 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
* generalized InvalidResourceException for parsing errors
* only iCals with both DtStart and DtEnd/Duration are processed (DtEnd will be derived by iCal4j when not present in .ics)
* all-day events must last at least one day (fixes#166)
* other DtEnd/Duration rewriting + tests