Merge pull request #360 from rjdowdall/master

Fixed some math functions and added more exceptions.

py/intdivmod.c

+#include "mpconfig.h"
+
+machine_int_t python_modulo(machine_int_t dividend, machine_int_t divisor) {
+    machine_int_t lsign = (dividend >= 0) ? 1 :-1;
+    machine_int_t rsign = (divisor >= 0) ? 1 :-1;
+    dividend %= divisor;
+    if (lsign != rsign) {
+        dividend += divisor;
+    }
+  return dividend;
+}
+
+
+machine_int_t python_floor_divide(machine_int_t num, machine_int_t denom) {
+    machine_int_t lsign = num > 0 ? 1 : -1;
+    machine_int_t rsign = denom > 0 ? 1 : -1;
+    if (lsign == -1) {num *= -1;}
+    if (rsign == -1) {denom *= -1;}
+    if (lsign != rsign){
+        return - ( num + denom - 1) / denom;
+    } else {
+        return num / denom;
+    }
+}

py/intdivmod.h

+// Functions for integer modulo and floor division
+
+machine_int_t python_modulo(machine_int_t dividend, machine_int_t divisor);
+machine_int_t python_floor_divide(machine_int_t num, machine_int_t denom);