FS#10187:Theme Deleter - Parses CFG files and removes their files

[川島 輝彰]

Hi, all.
I'd commit that if no one object.
It is a plugin to remove theme files.
See the task FS#10187 ( http://www.rockbox.org/tracker/task/10187 ) for
details.
There are test builds on the forum(see
http://forums.rockbox.org/index.php?topic=22369.0 ) for about two months
and no one has reported problem.
So, I think it's ok to commit.
If you have any opinions, please let me know.
Teruaki.