avoid strAddress + validity checks
avoid strAddress + validity checks

Avoid references to addresses using strings, and use CBitcoinAddress
as much as possible. Also added some validity checks on addresses
entered using RPC.

Cannacoin-Project/Cannacoin,bmp02050/ReddcoinUpdates,bmp02050/ReddcoinUpdates,coinkeeper/2015-06-22_18-46_reddcoin,coinkeeper/2015-06-22_18-46_reddcoin,reddink/reddcoin,bmp02050/ReddcoinUpdates,reddink/reddcoin,joroob/reddcoin,joroob/reddcoin,coinkeeper/2015-06-22_18-46_reddcoin,joroob/reddcoin,ahmedbodi/poscoin,ahmedbodi/poscoin,bmp02050/ReddcoinUpdates,ahmedbodi/poscoin,reddcoin-project/reddcoin,reddink/reddcoin,joroob/reddcoin,reddink/reddcoin,joroob/reddcoin,coinkeeper/2015-06-22_19-10_cannacoin,ahmedbodi/poscoin,Cannacoin-Project/Cannacoin,Cannacoin-Project/Cannacoin,coinkeeper/2015-06-22_18-46_reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,coinkeeper/2015-06-22_19-10_cannacoin,coinkeeper/2015-06-22_19-10_cannacoin,reddink/reddcoin,Cannacoin-Project/Cannacoin,ahmedbodi/poscoin,Cannacoin-Project/Cannacoin,coinkeeper/2015-06-22_19-10_cannacoin,coinkeeper/2015-06-22_19-10_cannacoin,coinkeeper/2015-06-22_18-46_reddcoin,bmp02050/ReddcoinUpdates,reddcoin-project/reddcoin