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.

src/coperators.h

@@ -37,6 +37,7 @@ typedef enum {
     OP_SUB,
     OP_MULT,
     OP_DIV,
+    OP_MOD,
     OP_NOT,
     OP_NEGATE,
     OP_COUNT,