Update Radegast to 2.8

This represents a major change to the packaging of Radegast.

The arch has been changed from 'any' to ('i686' 'x86_64') in light of
native libraries being used rather than being purely managed code.

makedepends have changed to no longer require nant, but now includes
dos2unix so the shell scripts can properly execute and recode to
convert a silly encoding in the license file to UTF-8 instead.