Batch converter bugs and nitpicks

[IXix]

A few small and old but very annoying batch converter issues...

1. Changing presets doesn't seem to update the file replacing logic. I have presets for mp3 and FLAC. If I convert a wav to mp3 and then select my FLAC preset and hit convert, I get prompted with a "somefile.mp3 already exists..." dialog and I have to manually reselect FLAC from the codec box before it will let me proceed.

2. The dither and noise shaping checkboxes aren't stored/restored properly from presets. My FLAC preset was saved with them both checked but every time I select the preset I have to recheck the two boxes.

3. (Nitpick) The "FLAC encoding depth" and "Data compression" dropdowns are disabled but not grayed when converting to FLAC. Likewise the mp3 "Mode" and codec info button are disabled but not grayed when converting to mp3. There may be other similar discrepancies with other codecs too, I haven't checked them all.

Win7 32bit if it matters

In the tracker: http://forum.cockos.com/project.php?issueid=5291