Clean warnings

[a-a-maly]

There should be no compiler warnings with -O3 -Wall -W.
Lots of them may hide really dangerous ones.
warn1.log

Something should be done with -D_CRT_SECURE_NO_WARNINGS -D_SCL_SECURE_NO_WARNINGS for VS compiler.

Remove -DNDEBUG -DQT_NO_DEBUG for Release build, asserts should be checked in production as well.
Remove -O2 for Release build, there is no reason to override default -O3.