Turn on all of Microsoft's recommend lint rules

Biggest changes forced by this: alt tags for all images, resulting in
new strings added to messages.json, and a new i18n paramter/prop added
in a plot of places.

Another change of note is that there are two new tslint.json files under
ts/test and ts/styleguide to relax our rules a bit there. This required
a change to our package.json script, as manually specifying the config
file there made it ignore our tslint.json files in subdirectories

ts/types/Message.ts

@@ -100,5 +100,6 @@ export const hasExpiration = (message: Message): boolean => {
   }
 
   const { expireTimer } = message;
+
   return typeof expireTimer === 'number' && expireTimer > 0;
 };