Merge branch 'release/0.3.0' into develop
Added support for channels based on thread ID for web driver manager.
support for multithreaded tests

move the exit hook into the destructor.

unit test for web driver manager teardown
use matchers instead of hard coded values in unit test.
code cleanup
tryout ghost driver on the tragis CI plan.
re-add the sauce config
flatten out desired capabilities when multi level keys are used.
update changes doc
bump up version number.
Merge branch 'release/0.3.1'