* changing felt script to fetch flutter
* changing the clone_flutter.sh code
* running integration tests with felt on cirrus. fetch framework in CI (not in local).
* only run cirrus tests on chrome. fix a comma in the flutter command path
* adding comments to public flags
* use local engine parameter for flutter pub get
* change flutter executable used for flutter drive command
* fix a cleanup issue. address comments. add toolException. enable web in flutter
* address reviwer comments. fix issue with local-engine
* address reviwer comments. fix issue with local-engine
* using engine/flutter/.dart_tools as clone directory. enabling clone script for local usage
* clean flutter repo with felt clean. add a flag to skip cloning the repo. always clone the repo even for local development, unless this flag is set
* fixing typos. updating readme for the new flag.
* fix directory error
* addressing reviewer comments
