Speeding filter up

Surprisingly, there is still a room for improvement!

One of internal functions of filter module was sligthtly changed, which lead to function speed increase 80-100 times, which, in turn, lead to overal filter speed increase c.a. 20%.

Among other updates, main programs input validation is getting better all the time.

Internal improvements

Almost no changes visible to user (except for some minimal GUI reactions improvement) yet some valuable internal changes like reduced memory usage for "Averager" ("POV-Ray Thread" is not supposed to work with large images anyway). From developer point of view, modules got changed so that many functions became private and aren't making a mess with "help" and docs anymore.

Having a ReST

ReStructuring docstrings to achive more legibility.

Validation, bugfixes

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

Filter improvement

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).

I've got to admit it's getting better, a little better all the time

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

Acceleration

Export optimization, better caching. Some minor internal changes.

Maintenance

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".

1.20.20.1 Maintenance

Maintenance update, code harmonization, improved GUI, etc.

Substantial filter update

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.