This is a variation on pull #755
I made the option -bip16, defaults to 1 (true).
I also moved the logic for setting the switchover time into init.cpp, and set the current-anticpated-switchover-time to March 1 for main network (left it at Feb 15 for test network).
I also changed the SoftSetArg(…bool) method’s name; during testing I was getting bitten by C++’s annoying habit of converting char* to bool instead of string.