Item12671: switch autobuild to Getopt::Long

this introduces:
    --autobuild (previously: -sven)
    --stable (build configured stable branch instead of trunk)
    --update (update this script from svn)
    --verbose

git-svn-id: http://svn.foswiki.org/trunk@17115 0b4bb1d4-4e5a-0410-9cc4-b2b747904278
Item12671: fix checkout of stable branch

also: log removal of unknown files, allow working/tmp to already exist

git-svn-id: http://svn.foswiki.org/trunk@17116 0b4bb1d4-4e5a-0410-9cc4-b2b747904278
Item12671: make webspace configurable

git-svn-id: http://svn.foswiki.org/trunk@17117 0b4bb1d4-4e5a-0410-9cc4-b2b747904278