Update chainparams.cpp, add regtest
Update chainparams.cpp, add regtest

Fix regtest and recalculate genesis block

- remove old testnet copy as regtest
- set new nonce for regtest 574752 (hex 574752 in text is ION)
- regenerate new genesis block hash
- add missing settings/parameters
- **TODO** - fix main.cpp, pow.cpp to
  - main.cpp
    `ERROR: ConnectBlock() : reward pays too much (actual=23.00 vs limit=0.00)`
  - pow.cpp
    `CheckProofOfWork() : hash doesn't match nBits`

cevap/ion,ionomy/ion,ionomy/ion,ionomy/ion,cevap/ion,cevap/ion,ionomy/ion,cevap/ion,cevap/ion,ionomy/ion,cevap/ion,ionomy/ion