Add carryBit, miscellaneous fixes
Fix CPD test, forgot to decrement BC and set P/V correctly
Reset updateParity to use popcount, fix small issue in flags.S and add flags 3 and 5 to print_state
Fix broken test
Implement echo_reg
Have main.c print_state use print_state (the function)
Add unhalt command
Merge branch 'master' of https://github.com/KnightOS/z80e