Merge pull request #3824

f0a83fc Use Params().NetworkID() instead of TestNet() from the payment protocol (jtimon)
2871889 net.h was using std namespace through chainparams.h included in protocol.h (jtimon)
c8c52de Replace virtual methods with static attributes, chainparams.h depends on protocol.h instead of the other way around (jtimon)
a3d946e Get rid of TestNet() (jtimon)
6fc0fa6 Add RPCisTestNet chain parameter (jtimon)
cfeb823 Add RequireStandard chain parameter (jtimon)
21913a9 Add AllowMinDifficultyBlocks chain parameter (jtimon)
d754f34 Move majority constants to chainparams (jtimon)
8d26721 Get rid of RegTest() (jtimon)
cb9bd83 Add DefaultCheckMemPool chain parameter (jtimon)
2595b9a Add DefaultMinerThreads chain parameter (jtimon)
bfa9a1a Add MineBlocksOnDemand chain parameter (jtimon)
1712adb Add MiningRequiresPeers chain parameter (jtimon)