Fix socket_io memory-alloc bug.

Fix:
	src/socket_io.c
		-sendPacket() never deallocated `char * received_buffer`, which was
		malloc'd to a 1000 bytes; after some seventy calls, bin/chat_client
		would crash due to an inability to further malloc memory.
		-attempting to free() the pointer threw a double-free error
		-solve by declaring `char received_buffer[1000]`