Merge RegionMemberCommands into RegionCommands

remove RegionMemberCommands and put the add/remove - member/owner
commands in RegionCommands using/'to fit with' the up dates in the
commit d61e32ebb5a8d7e21cb117cf84fe1c9332609197
Merge branch 'master' of https://github.com/NineteenGiraffes/worldguard