Warning fixes

I've gone through and cleaned up all the Astron related warnings. Apple depreciated OpenSSL for Crypto when OS X 10.7 was released (If memory serves me right, or something along those lines) so all those warnings are still present, however Astron still runs fine. These are all just minor fixes, but they have been bugging me for quite some time.

I have tested this and everything appears to run A-OK :+1: 
Again the best solution here would be to specify the methods as virtual (really all the methods from send disconnect down).   Note that send_disconnect defined in the class will override Client::send_disconnect because the function prototypes match.   You may still need to have one of these using statements to get rid of errors, but I'd try removing both of them at first.