Use the new format of setting tags in view extension (Debian bug #361897)

Never exit directly from commands.dispatch(), but pass return code to caller. Usually the caller is commands.run(). Some extensions still use sys.exit(), this is catched, too. Fixed wrong return statement in commands.recover() yielding a zero exit code.

Polished exception handling when importing extensions: - Warning about failed import is printed on one line. - For this warning the [extensions] section key is used, because the value doesn't have to be set. - Whan a --traceback is requested, exit immediately to not mix up problems when importing an extension with other problems.

Added doc/gendoc.py to MANIFEST.in, so docs can be regenerated on demand.

fix exception handling on windows. move win32 code into util_win32.py.

Include tests/md5sum.py in manifest.

Added tag 0.8.1 for changeset 6a03cff2b0f5d30281e6addefe96b993582f2eac

Try to use /usr/bin/test or /bin/test to work around missing features. The builtin "test" of Solaris 8 /bin/sh doesn't understand -nt.

util.copyfiles: only switch to copy if hardlink raises IOError or OSError. before this, interrupting clone would give "file a same as file b" error because caught KeyboardInterrupt.

Make completion for debugindex<tab><tab> show debugindexdot, too. The special handling for commands with names that are substrings of other commands (e.g. with st and strip) wasn't used with debug commands before.