make SegmentType an global enum class
update mtest
fix #25929
25921
ParDescr is a struct, not a class
don't compare pointers against NULL in C++11

either avoid it like done here or use nullptr
use correct format specifiers

%d rather than %ld for int resp. %hhd vs. %d for char
add int to string the Qt way
disable bindings completly

not just the content
disable unused private members
disable unused local variables
initialize variables
avoid unused variable (and code) in RELEASE mode