Fixes
- Bitrate conversion doesn't throw an exception if the user fails to put all relevant fields in
- subs.ass/subs.srt IO errors wont occur if the file exists now
- Subtitles no longer get cropped off
- txtCrop will now change to black when the user types into it
- comboQuality now has a warning for Ultra Quality
- btnClear now actually clears EVERYTHING (forgot about audio)