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

tools/js2dart/karma-traceur-preprocessor.js

@@ -0,0 +1,61 @@
+var traceur = require('traceur');
+
+var createTraceurPreprocessor = function(args, config, logger, helper) {
+  config = config || {};
+
+  var log = logger.create('preprocessor.traceur');
+  var defaultOptions = {
+    sourceMaps: false,
+    modules: 'amd'
+  };
+  var options = helper.merge(defaultOptions, args.options || {}, config.options || {});
+
+  var transformPath = args.transformPath || config.transformPath || function(filepath) {
+    return filepath.replace(/\.es6.js$/, '.js').replace(/\.es6$/, '.js');
+  };
+
+  return function(content, file, done) {
+    log.debug('Processing "%s".', file.originalPath);
+    file.path = transformPath(file.originalPath);
+    options.filename = file.originalPath;
+
+    var result = traceur.compile(content, options);
+    var transpiledContent = result.js;
+
+    result.errors.forEach(function(err) {
+      log.error(err);
+    });
+
+    if (result.errors.length) {
+      return done(new Error('TRACEUR COMPILE ERRORS\n' + result.errors.join('\n')));
+    }
+
+    // TODO(vojta): Tracer should return JS object, rather than a string.
+    if (result.generatedSourceMap) {
+      var map = JSON.parse(result.generatedSourceMap);
+      map.file = file.path;
+      transpiledContent += '\n//# sourceMappingURL=data:application/json;charset=utf-8;base64,';
+      transpiledContent += new Buffer(JSON.stringify(map)).toString('base64') + '\n';
+
+      file.sourceMap = map;
+    }
+
+    return done(null, transpiledContent);
+  };
+};
+
+createTraceurPreprocessor.$inject = ['args', 'config.traceurPreprocessor', 'logger', 'helper'];
+
+
+var initTraceurFramework = function(files) {
+  files.unshift({pattern: traceur.RUNTIME_PATH, included: true, served: true, watched: false});
+};
+
+initTraceurFramework.$inject = ['config.files'];
+
+
+// PUBLISH DI MODULE
+module.exports = {
+  'preprocessor:traceur': ['factory', createTraceurPreprocessor],
+  'framework:traceur': ['factory', initTraceurFramework]
+};