CDB-1175 #resolves Fixes failing spec
CDB-1205 #resolve - Fixes #306 - problem when mixpanel is not loaded
checking mixpanel from window variable
mixpanel methods running from window as well
Merge remote-tracking branch 'origin/fix/CDB-1175' into release/2.6.0
Merge remote-tracking branch 'origin/bug/CDB-1205' into release/2.6.0