S2EExecutionState: CPU_REG_SIZE CPU_REG_OFFSET

Add CPU_REG_SIZE and CPU_REG_OFFSET macro defines

Signed-off-by: Michael Contreras <michael@inetric.com>
ConfigFile: x86_64 support

Signed-off-by: Michael Contreras <michael@inetric.com>
MMUFunctionHandlers: make indexes target_ulong

Signed-off-by: Michael Contreras <michael@inetric.com>