ReStructuring docstrings to achive more legibility.

Improved user input validation; fixed bug with capitalized file extensions handling.

In the course of selfless struggle to exterminate an elusive bug, filter module met with major two-lines change substantionally changed its logic in an uncertain situations, making this update a must.

In the meantime, several updates were introduced providing some speed increase.

Main GUI got several new keybingings for zoom 1:1, namely Ctrl+1 (like Macromedia Fireworks, hallowed by its name) and Ctrl+ALt+0 (like Adobe Photoshop).

Filter improvements for better resource usage and speed; some improvements in UI code.

Export optimization, better caching. Some minor internal changes.

Maintenance update, mostly due to PyPNM update to ver. 2.21.2.2 "Victory II", more resource saving as compared to 1.17.9.34 "Victory".

Maintenance update, code harmonization, improved GUI, etc.

Update mostly related to filter, rewritten to fully support any color mode (L, LA, RGB, RGBA). Added wrap around processing for seamless textures and options for protect alpha/filter alpha channel.

Averager.py GUI rewritten to work with new filter features, more informate "Info" added, filtered/saved status shown to mimic Photoshop/Fireworks/Paint Shop Pro.

POVRayThread.py got minimal update to cope with new filter.

Main program GUI improvements ans unification. Main modules remain the same as for 9 May "Victory".

New, more compact menu-based GUI, with Photoshop-like zooming plus mouse wheel zooming, and other interface improvements.