Enabled ClipPaths option to filter letters.

[savasozer]

I hope I've implemented correctly.

[jerrosenberg]

Anything I can help with to rework or tie this up? The change works for my case. Does it just need more comprehensive tests or you want coverage of more cases? I'm not sure all cases will be covered first round. Could add a ClipText option so that this functionality is opt in for now, and people can open new issues for additional cases that don't seem to be covered. Thoughts? Thanks.