Fix compilation issue and add support for AS 2.2+

Bump client library version

Bump version for beta 4

Bump version numbers for beta 3

Merge pull request dronekit#389 from chaviw/version_bump

Updated library and service version

Bump version for beta 1

Update client library dependencies to fix travis build issues

Merge pull request dronekit#57 from 3drobotics/release-1.5.1

Release 1.5.1

versions bump for release.

version bump for beta 2.