micro:coin activity (#650)

* microcoincode

* adding links

* fix file name

* a bit more docs

* Some minor edits

* Add a crypto blurb

* missing radio package

* updated info

* link to wallet activity

docs/projects/wallet.md

@@ -10,6 +10,11 @@ Make a @boardname@ wallet with this guided tutorial!
 
 ![wallet image](/static/mb/projects/wallet/wallet.jpg)
 
+## Activities
+
+* [Make](/projects/wallet/make)  
+* [Code](/projects/wallet/code)
+
 ## ~button /projects/wallet/make
 
 Let's get started!