build: execute pub get and dart analyzer

When chaining a `pubspec.yaml` we automatically run `pub get`.

In `gulp build` we also run `dartanalyzer` for all files
that have the pattern:

`<module>/lib/<module>.dart`

Closes #13
Closes #5
Closes #2

modules/facade/test.dart

@@ -1,13 +0,0 @@
-import 'dart:core' as core;
-import 'dart:collection';
-
-class Map  {
-
-  new() => null;
-
-  ping() => core.print('map');
-}
-
-main() {
-  new Map().ping();
-}