Merge pull request #1 from samwho/master

IT BOOTS!
More work on making mruby compile against boot.rb.
Fix atoi() bug. Thanks @samwho.
Almost compiles.
Closer.
Fix more things.
getchar()/fgets()!
It successfully compiles mruby! (even without all the functions defined. because libraries.)
Add fwrite() and bullshit math functions.
Fix atoi().
It compiles, now.
Actually build correctly.
Crappy realloc() implementation.
Add a comment about how shitty realloc() is.
Add mirb-related stuff.
It actually compiles correctly, now.
Force mirb.c to be regenerated every time kernel.bin is built.
Add setjmp/longjmp. This didn't fix mirb, though.
STUFF.
Split test boilerplate out into separate files.