Add armor suggestions

I also changed a lot of the version comparison logic to be more sensible
by using comparable constants instead of always checking multiple
strings.

src/Constants.js

@@ -0,0 +1,10 @@
+// Constants for easily handling supported minecraft versions.
+// Earlier versions should have lower numbers, so that comparisons work as expected.
+export default {
+    MC_1_8: 1,
+    MC_1_9: 2,
+    MC_1_11: 3,
+    MC_1_13: 4,
+    MC_1_14: 5,
+    MC_1_16: 6
+}