Add variables and add

tests/simple.grnd

@@ -1,3 +1,19 @@
-@myLabel
-println "dingus"
-jump %myLabel
+# Check setting variables
+set &myVar "dingus"
+println $myVar
+
+# Check string concat
+add "dingle" "fart" &myOtherVar
+println $myOtherVar
+
+# Check double math
+add 3.14 2.7 &myThirdVar
+println $myThirdVar
+
+# Check int math
+add 464398727 374298 &yetAnotherVar
+println $yetAnotherVar
+
+# Check mixed math
+add 432 4732.12 &finalVar
+println $finalVar