Issue #17: displaying trek images in "browser" mode
Updating $compileProvider to allow "cdv://" protocol in ng-src directive
Issue #7: Adding trek pictures download + correct img file serving (replacing image url with adapted remove/local ones)
Issue #17: Adding POIs thumbnail in online mode
Issue #17: downloading and serving poi thumbnail and pictures in offline mode
Issue #17: Moving remote constants to app main module
Issue #17: moving FileSystem constants to app file
Moving settings values to separate file (avoiding domain name and other values duplications in previous angular constant case)