Prepare Alpha 0.0.9 (flutter#10712)

Bump version in preparation for new tag (flutter#10689)

flutter#10688

Release SDK version 0.0.7 (flutter#10456)

Rev alpha branch version to 0.0.6, flutter 0.0.26 (flutter#10010)

VERSION: 0.0.6
flutter: 0.0.26
flutter_driver: 0.0.4
flutter_test: 0.0.4

Merge pull request flutter#779 from abarth/basic_docs

Add some dartdoc to basic widgets