Proper processing for pre-modded sprite packs

[Laforeta]

Considerations for these files:

1. They may have mismatched tags - need to use swfextract instead of ffdec.
2. They will, more likely than not, have whitespace surrounding images so images with alpha layer must be trimmed.
3. Replacement will be hard as many peculiarities are expected with borked frame structure. It may be eaiser to request the stock sprite back and use it as a starting point

[Laforeta]

Subroutines added to

IMPORT EXTRACT SCALE

and will be added to

REPLACE EXPORT ONECLICK

once ffdec binary has been updated to allow reomoving unused characters.

[Laforeta]

Compiled new ffdec binary, testing now

[Laforeta]

Closed in #27

[Laforeta]

Incorrectly closed this one instead of #20. Reopening issue.

[Laforeta]

Detection mechanism is problematic: Files with .hack.swf suffix will enter both STOCK and MOD streams, nothing works beyond this point