Orphaned .VBP update
Move progress bar to its own window

Warning: large commit!

Removing the program's old universal progress bar has proven more
challenging than I originally anticipated.  (Imagine that.)

Rather than try and shoehorn it into a picture box on image forms, I
have simply given it its own form, which receives special treatment as
necessary.

Note that *batch conversion is still broken* in this dev version.  It
will take some work to get it properly sorted out, so please use the
stable version for all batch conversion tasks.