Modify tag regex to deal with tabs in 'ex_cmd'

- Integrate changes suggested by 'scriptkitz' for issue #209

    https://github.com/SublimeText/CTags/issues/209
Append 'r' prefix tag regex strings

- The tag regex is an example of a raw string. Mark it as such.

    http://stackoverflow.com/q/4780088
Merge branch 'bug/209' into development