* Add asserts for correct behaviour of Overflow flag
* Switch to smtbmc engine in prove mode (much faster than abc)

* Remove unused SVA properties file
* Makefile optimizations
* Use prep auto-top option to prevent error with not founded top-level module
* Rewrite assignments of Dout_o & Overflow_o as GHDL synthesis don't
  support concatenation on left side of assignments
* Add some simple PSL assertions

* Adopt init state generation for initial reset constraining
* Add assume about inactive reset after initial active
* Replaced OPC consts by macros
* Replace SVA reset check by simple unclocked immediate assertion