Added modulo operator '%'

- added OP_MOD, which performs a modulo operation on the 2 <number> values on the stack. Pops the 2 values and pushes the result.
- also added TOKEN_PERCENT to the lexer, and extended binary() in cparse.c to support it.

Makefile

@@ -2,7 +2,7 @@
 
 CC=clang
 CFLAGS=-fPIE -Wall -O3 -std=c11
-LDFLAGS=#-fsanitize=address
+LDFLAGS=-lm #-fsanitize=address
 OUT=bin/cosmo
 
 CHDR=\