Fix bug in computing regiser addresses.

src/e-server:
	* src/CoreId.cpp (operator<<): Use 2 chars for column as well as row.
	* src/GdbServer.cpp (GdbServer::regAddr): Increment reg addresses
	by 4 bytes.
	* src/GdbServer.h: Make regnums unsigned ints
	* src/TargetControlHardware.cpp (TargetControlHardware::readMem):
	Slightly simpler formula to map buf to data.