Fixed: on a second thought, let's just make FileImageReader fall back to guessed image if possible...

Fixed: made more correct checking for legal file formats; now it should actually validate the format upon loading

Fixed: flats are now unconditionally detected as Doom Flat if they are exactly 4096 bytes long and inside F_ markers or flats directory.  (reported by Chickenlegz)

Enabled parsing of NaN in UDMF so that the existing buggy maps load;  made it throw exceptions when a NaN vertex is added to the map

Did some maxcode refactoring about dynamic lights;  added initial spotlight support (at least they are recognized as lights now)

Added support for non-1.2 pixel ratios if view stretching is enabled (reported by Nash);  Fixed: map names in quotes were not recognized properly.

* Mouse selection threshold

* Cleanup

* Fix selection bug

- Dialog can't be resized anymore
- Dialog can be canceled by pressing the escape key
- Changed input boxes to the appropriate GZDB version, so steps and modifier key work correctly
- Added checkboxes to automatically fit the textures optimally based on the width/height of the line(s) in respect to the width/height of the texture
- Added input boxes to manually set a width/height pattern size of the texture that will be used when automatically fitting textures

Fixed: INHERITACTORPITCH was actually changed along with USEACTORPITCH...doesn't really make sense compatibility-wise but there it is. (reported by alekv)

Fixed: pitch formula was duplicated and not changed in one of the places. (reported by Ozymandias81)

Fixed: flipped +USEACTORPITCH direction for recent GZDoom versions;  this can be reverted by putting "buggymodeldefpitch = true;" in the game configuration for your specific projects if they are using old GZDoom versions.  Note: already added for Zandronum.

Fixed: render sorting issues with multiple translucent 3D floors next to each other on different heights