release.sh:
- Add a VCSCMD variable that defaults to 'svn checkout',
  and update places 'svn co' is used directly.
- After sourcing a configuration file, prefix SRCBRANCH,
  PORTBRANCH, and DOCBRANCH with the SVNROOT.
- Properly capitalize 'FreeBSD.org' in the default SVNROOT.
- Update Copyright.

release.conf.sample:
- Add an example to use git instead of svn, by nullifying
  SVNROOT, and setting SRCBRANCH, DOCBRANCH, and PORTBRANCH
  to the URL fo a git repository.

release.7:
- Document VCSCMD.

Submitted by:	Rick Miller (based on)
Sponsored by:	The FreeBSD Foundation