Cleanup a bit and TODOs

Still to do:

* Exposing functions

  * instead of `$scope.$parent[attr.name]` & `this.addTrack = function`
  * it would be nicer to do `$scope.genBrowserOptions.addTrack = function`

* Size

  * add an option in genBrowserOptions to set a fixed sized

  * instead of `window.height() - footer.height()`
     this might be more correct ?

        ```js
        prevElems = $element.parentsUntil('body').prevAll(':visible');
        nextElems = $element.parentsUntil('body').nextAll(':visible');
        $(window).height() -
              sum(prevElems.add(nextElems).map(function(){
                     return $(this).height();
              }))
        ```
* dontLoad

   * DontLoad seems to be assignet in async function `$scope.browser.getStore` but used in sync
     it probably sets the value too late / reads it too soon
$scope.browser._storeCache shouldn't be deleted, only the "refseqs" property.