[ucsim-mos6280] Fix [bugs:#4075] uCsim incorrect STA ZP,X for HuC6280
[ucsim] Fix print of errmsg
[r16871] Place of ZP is configurable with ZPh variable, on 6280 it's 0x2000 by default. Manual of the 6280 doesn't say that MPR1 is not used for ZP... This revision still uses mapping, but at 0x2000.
[ucsim-mos6280] Fix [bugs:#4075] uCsim incorrect STA ZP,X for HuC6280
[ucsim] Fix print of errmsg
[ucsim-mos6280] Fix init of MPR0-MPR6
[ucsim-mos6502] Config variable for high half of SP
[ucsim-mos6280] Map all 8k chunks to different memory by default (not hw compilant)