remove old code useless code found by pylint "(unnecessary-pass) Unnecessary pass statement"

fix error found by pylint 'W0104(pointless-statement) Statement seems to have no effect'

fix pylint warning "(undefined-loop-variable) Using possibly undefined loop variable 'X'"

fix pylint warning 'C0112(empty-docstring) Empty function docstring'

fix pylint warning "(relative-import) Relative import 'Y', should be 'X.Y'"

fix pylint warning '(dangerous-default-value) Dangerous default value {} as argument'

fix pylint warning '(old-style-class) Old-style class defined.'

This warning is ignored for classes from PyJSLib, because library
overrides base object class.

fix pylint warning '(unused-import), Unused import connectors'

fix typos

comment out unused code SFC_Step.RefreshBoundingBox()

explicitly mark unused variables found by pylint with _ or dummy

pylint don't ignores unused variables with '_' in the name, even when
they are started with '_'. This bug is already fixed upstream, to fix
this in all versions of pylint custom dummy-variables-rgx is used
'_+$|(_[a-zA-Z0-9_]*[a-zA-Z0-9]+?$)|dummy'

remove unused variables found by pylint

update .PHONE target in Makefile for mki18n.py

make mki18n return 0 on success