Memory routine additions & better testing
* Created memset. I haven't tested this yet. I'm assuming it works for now
* core.S clears the BSS during init
* modified kernel linker script. (Yes I know it looks odd right now)
* Removed division testing code in c_start
* Made a way to start qemu in testing mode in the Makefile by creating a new target called 'drun'. Short for 'debug run'.
* Changed the testing target in the Makefile from 'qemu' to 'run'