Support annotation-plug-in

[micw]

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

Feature

• What is the new behavior (if this is a feature change)?

Support annotation-plug-in. Closes #63

• Other information:

[micw]

Please have a special look into 703248f:

The current behaviour was to update the state and call the "updateData" function. This triggered both, the state change client code as well as the "update data" function. Since the state change is always triggered, it's not possible to update data without updating the state.
In the commit I enabled initial support for updating the options (did it for legend, others are similar but need some testing). So I renamed refreshData() to update() and deprecated refreshData() because the supported options will always be updated together with the data.
There's no need to call the updateData function anymore.

Edit: an alternative approach would be to separate data and options and update both by independent function calls. The drawback is that the chart has only one update() function, so it would needed to be called twice.

[moberwasserlechner]

I try to have this reviewed and tested by the end of this week. BR

[moberwasserlechner]

Could you please add a demo view for this feature as well?