add initial facade
add groups, fix events
add alias facade
add page facade
refactor #_invoke
cleanup
Merge remote-tracking branch 'origin/master' into add/facade
group properties => traits
track properties
remove isodate-traverse, facade already does this
use facade.enabled() and remove isEnabled()
remove not needed test
1.2.0

* add [`facade`](https://github.com/segmentio/facade)