Use a fixed-size buffer for log messages

libc++'s implementation of ostrstream seems to have incorrect
range-checking and does some out-of-bounds reads and writes whenever a
resize is needed, which results in crashes on 10.7 (but not 10.9 for
unknown reasons).
Preserve the filename header when reading attachments
Codesign the app bundle before creating the dmg
Get the UI font from CoreText on OS X
Eliminate CoreText warnings on 10.9 from the audio track cursor
Fix crash when writing crash logs
Also add the track cursor font name option to the non-OS X config file
Fix crash when FFMS_GetCodecNameI returns NULL
Update ffms2 version
Fix AssAttachment::Clone
Remove pointless sizer in the colorpicker dialog
Fix the color picker recent colors box on OS X

SetBitmap triggers a size event, which results in UpdateBitmap being
called again. For some reason, rather than being an infinite loop this
just resulted in the bitmap never being set.
Merge branch 'master' of github.com:Aegisub/Aegisub into retina
Rewrite