While is working but untested, read more

* TODO: break and continue keywords need to be implemented
* TODO: while-then needs testing
* Fixed the parser not liking zero-length strings

scripts/looping.toy

@@ -0,0 +1,9 @@
+var a: int = 0;
+
+while(a < 10) {
+	print a;
+	a += 1;
+}
+
+print "Finished";
+