Continue working on FParser JIT

* Path fix for Linux
* Add optimizer opcodes, fix bugs
* Vastly expand JIT opcode support, fix AD bug... oops!
* Add JIT support for if(a,b,c) control flow opcodes
* Make compares fuzzy using Fparser's epsilon
* Fix compile error when fpoptimizer is disabled
* Enable support for more Value_t types
* Fix stack recover bug, add test/example
* Add performance test code
* Fix another AD bug involving cDup
* Tweak/expand tests