#1292 font and colors dialog slow to pop up now because of fonts query

[Jeremy Faden]

For more than a year now Autoplot queries the fonts to see which fonts can be embedded with PDF files. This is done before the font and colors dialog is shown, and it's slow enough that it needs to be done elsewhere.

1. [menubar]->Options->Fonts and Colors
2. after a few seconds the dialog finally pops up, with an indication of whether or not the current font can be embedded.