Remove frame count when only one frame. Fixes #5.

The frame count suffix is only added when there's more than one frame in the swf.
Pad output frame count with zeros. Fixed #7.

This should make sorting in finder, or when using fileglobs easier.
Filenames with spaces are now valid. Fixes #4.

The output filename prefix wasn't detected properly, and behaved incorrectly when filenames had spaces in them.
Command-line tool for batch processing.

This is one step on the way to resolving #3. These features will hopefully be integrated into the app directly.
Update README to reflect addition of swfs2pngs.
Bump version number to 0.3.0.