Speed up the Z3 backend by using low-level Z3 APIs (#119)
Speed up the Z3 backend by using low-level Z3 APIs (#119)

* Easy z3 functions reimplemented using low level API

* Medium z3 functions reimplemented using low level API

* Done with z3 backend rewriting using only low level z3 API

* Fix linter errors

* Fix reuse z3 solver constraints caching

* Easy z3 functions reimplemented using low level API

* Medium z3 functions reimplemented using low level API

* Done with z3 backend rewriting using only low level z3 API

* Fix liter errors

* Fix reuse z3 solver constraints caching

* Fix wrong change during merge with wip/z3_speedup

* Fix key in dictionary check

angr/claripy