Add Gantt-chart widget

[aleastChs]

Code in Branch: googleTimeSeries

[aleastChs]

Solve this aleastChs/scalajs-google-charts#17 !!!
Created new branch googleLastCommitWorking for testing and it is fully working with scalajs-google-charts v0.4.3

Something goes wrong when merging with scalajs-react v1.1.0 or v1.0.0???

[aleastChs]

See:
aleastChs/scalajs-google-charts#17
for Error message with ericaBackend/run at:
237114c