Bumped version to '2.1.0-Preview.1'

Bumped version to '2.0.0'

Bumped version to '2.0.0-Preview.5'

Bumped version to '2.0.0-Preview.4'

Bumped version to '2.0.0-Preview.3'

Bumped version to '2.0.0-Preview.2'

Merge pull request microsoftgraph#179 from microsoftgraph/v2.0.0

Version 2.0.0

Bumped version to '1.7.0'

Bumped version to '1.7.0-Preview.3'

Bumped version to '1.7.0-Preview.2'