refactor: simplify and make tests work in JS and Dart

* remove `wraps` syntax enhancements for imports
  and support new `import * as module from ...` syntax

  - default imports are the wrong construct for importing
    everything from a module

* moved tests from transpiler to jasmine and karma

  - transpiler tests are included when running karma in main project folder
  - transpiler is reloaded after every test run in karma,
    so no need to restart karma when the transpiler has been changed.
  - removed own gulp build for transpiler and `postinstall.sh`
    as they are no more needed.
  - transpiler tests are now executed in Dart AND JavaScript (used to be executed
    only in Dart), which allowed to catch some bugs (see the bug with the
    import specification above).

* made tests work in dart as well by using the following hack:

  - dependencies are loaded from the `build` folder, which makes
    running `gulp build` necessary before running karma for dart
  - for this to work,
    the dependencies are included in main `pubspec.yaml` of project
  - reason for the hack: `karma-dart` loads all `packages` urls
    directly from disc (should rather use the karma file list)

* added explicit annotations `FIELD`, `ABSTRACT`, ... to `facade/lang.*`

  - needed for now that we can run tests and don't get errors for undefined
    annotations.

* added `README.md` with details about the build and tests

README.md

@@ -0,0 +1,49 @@
+## Build
+
+### Prerequisites:
+
+1. `npm install`
+2. `pub get`
+3. `install -g gulp`
+4. `install -g karma`
+
+### Folder structure
+
+* `modules/*`: modules that will be loaded in the browser
+* `tools/*`: tools that are needed to build Angular
+
+### File endings
+
+* `*.js`: javascript files that get transpiled to Dart and EcmaScript 5
+* `*.es6`: javascript files that get transpiled only to EcmaScript 5
+* `*.es5`: javascript files that don't get transpiled
+* `*.dart`: dart files that don't get transpiled
+
+### Build:
+
+1. `gulp build` -> result is in `build` folder
+
+  * will also to `pubg get` for the subfolders in `modules`
+    and run `dartanalyzer` for every file that matches
+    `<module>/src/<module>.dart`, e.g. `di/src/di.dart`
+
+2. `gulp clean` -> cleans the `build` folder
+
+### Tests:
+
+1. `karma start karma-js.conf.js`: JS tests
+2. `karma start karma-dart.conf.js`: JS tests
+
+Notes for all tests:
+
+The karma preprocessor is setup in a way so that after every test run
+the transpiler is reloaded. With that it is possible to make changes
+to the preprocessor and run the tests without exiting karma
+(just touch a test file that you would like to run).
+
+Restriction for Dart tests (for now):
+
+  * Due to a bug `karma-dart` plugin,
+    this will use the files in the `build` folder for resolving
+    `package:` dependencies (created e.g. for `import ... from 'di:di'`).
+    So you need to execute `gulp build` before this.