* Disable spinners for width/height unless fullscreen option is checked and re-label them as "FS Width/Height" to avoid confusion.
* Fix problem with ConfObject "default" key
* Set lowest audio sampling rate to be 8192 (which is the lowest mednafen will accept).
* Convert glade file to UI Builder format (along with required source changes).
* Make width/height spinners accept real numbers (i.e., floats) to allow for fractional adjustments.
* Make sure that "gtk-button-images" setting is True, so our buttons always have images.