Improved naming of the partfiles.

Previously the parts have filenames that are only "part.cfg", which
results in confusion in external Editors like Notepad++.
Now if useNamedCfgFile config paremeter is "true" then file named like
folder (for example "WeldedPod.cfg", not "part.cfg")
Fixed crashTolerance, breakingForce and breakingTorque calculation. Improved MaxTemp calculation.

Now there is three methods of calculation crashTolerance, breakingForce
and breakingTorque values:
legacy (UbioZur variant)
arithmetic mean value of the values of parts
weighted average by mass (now it's default)
The method is determined by the value of StrengthCalcMethod parameter in
config file

Also it presents new ways of calculation of MaxTemp:
arithmetic mean value of the values of parts (UbioZur variant)
weighted average by mass
lowest between values of parts  (now it's default)
The method is determined by the value of MaxTempCalcMethod parameter in
config file