Merge pull request #40 from openvv/generic_event_type2

changed eventhandlers to generic events to prevent runtime casting error...
Added impression unmeasureable event
Added impression unmeasureable event
fixing whitespace differences
Merge pull request #41 from openvv/detect_when_beacons_are_ready

Add not_ready state to viewabilityState for indicate when the beacons are not ready to determ if we can measure
Revert "Add not_ready state to viewabilityState for indicate when the beacons ar..."
Merge pull request #44 from openvv/revert-41-detect_when_beacons_are_ready

Revert "Add not_ready state to viewabilityState for indicate when the be...
Merge branch 'vmc-unmeasurable-event' of https://github.com/vmcbos/openvv into vmcbos-vmc-unmeasurable-event
expose OVVEvent.OVVImpressionUnmeasurable to third parties
updated unmeasurable threshold to a lower value
Merge pull request #45 from openvv/vmcbos-vmc-unmeasurable-event

unmeasurable event
Add not_ready state to viewabilityState