Fix bug where savePixmap settings.quality was incorrectly compared
to a string instead of an integer. Also ensures that arguments to
savePixmap are coerced to the correct types.
Merge pull request #182 from adobe-photoshop/jrb/convert-string-bug

Fix bug where savePixmap settings.quality was incorrectly compared to a string
Merge remote-tracking branch 'origin/master' into ps-next