pdTextBox: save text property in the IDE

I forgot that I actually make use of the .Text property in the IDE in a
few places...
Color selector dialog: convert hex input to pdTextBox

Validate event appears to work just fine, since we sorted out focus
issues using VB's own focus events - neat!
Sort out IDE user control icons
Batch Wizard: convert to pdTextBox
Import > Online image dialog: convert to pdTextBox
Language Editor: convert to pdTextBox

Best part about this?  Our Google Translate interop code works with
Unicode chars!  Some languages inexplicably fail (for example, Chinese),
but hey - it still makes me happy to see the text box auto-populate with
translated East Asian characters from the languages that do work.

Of course, this is pointless as long as PD's XML class can't read/write
Unicode, but I'll get to that in due time.