Don't treat exclude lines with embedded "+" characters as inclusions

Previously, this code prevented any file name with a "+" character from
being excluded.
Escape + in pattern for extra safety

The old version worked, but it seems like an accident that a "+" after a
"*" is treated as a literal "+" and not a repetition.
Ignore blank lines and rsync comments in excludes file
Merge pull request #221 from dreiss/config

Fixes for parsing excludes file