Add non-strict output verification.

[misaim]

Currently output file verification is reasonably strict:

re.sub('[^0-9a-zA-Z\.,:%\-_#]+', '', ebl_file['header_3']['filename'])

We should add a new flag and a secondary regex which allows some chars through for OS's where it doesn't matter - i.e Mac OS X and Linux both allow !, ? and ' ' chars in filenames, although windows doesn't.

Could also look at replacing some strings. '/w' is used for shorthand "with", / is used for time sig's and could be "slash" or a dash.

[jackbucinskas]

We should add a new flag and a secondary regex which allows some chars through for OS's where it doesn't matter - i.e Mac OS X and Linux both allow !, ? and ' ' chars in filenames, although windows doesn't.

Disagree.

[misaim]

Why disagree? Some chars are used - Like ' ' is perfectly fine. Known shortenings also. Some music-specific stuff too (# for sharp, * seems to be used for something(?), etc.