fix Language select and deprecated thresholds

[zvezdochiot]

Fine-tuning #146 .

Tuning #150 :

⚠️ Deprecated.

Threshold	Radius	Coef	Status
EdgePlus {kep,0}	5	0.75	deprecated, remove
BlurDiv {0,kdb}	5	0.75	deprecated, remove

☑️ Workers.

Threshold	Radius	Coef	Status
Sauvola	100	0.34	founder of the "Means" series
Wolf	100	0.30	current of the "Means" series
Fox	100	0.30	optimize resource
Window {without *3.0}	50	1.00	☑️ best of the "Means" series
Bradley	100	0.15	simple of the "Means" series
Grad	15	0.75	☑️ best of the "Hybrid" series
EdgeDiv {kep,kdb}	5	0.75	☑️ best of the "Prefilter" series

ws = Radius + 1 + Radius; Window_Size = QSize(ws,ws); (a derived quantity for using integral images instead of direct filtering).