Support for chart.inverted=true

[prusse-martin]

Properly position annotations on inverted charts when:

• linked to points;
• positioned using yValue and/or xValue ;
• drag/drop annotations along the correct axis when allowDragX or allowDragY are disabled (also correctly update the xValue and/or yValue);

[prusse-martin]

Some jsfidles:

• showing the behavior with blacklabel:master: http://jsfiddle.net/2ay85n5b/
• using the code of this PR: https://jsfiddle.net/2ay85n5b/3/

(to see the effect over updating the xValue and yValue value open the console)

[pawelfus]

Thank you for sharing! Somehow I got distracted and missed this PR. I will review soon. I guess it's the same as PR: #66 ?

[prusse-martin]

Yes it looks like that have the same general feature in mind.
I didn't run a fiddle testing it but maybe his change in redraw visually compensates for my changes in translateAnnotation.
One will need to check if programmatically inspecting the notes after "mouse translation" yields good or weird values. Maybe editing/copying one of the fiddles I added to this PR and maybe adding some missing case to get a more thorough check.
I got to understand the code to edit it at the time but that didn't make into my long term memory, sorry.

[pawelfus]

Thanks for your feedback! My apologies for missing this PR once again. I just merged the second PR, so closing this one.

[prusse-martin]

Check the jsfiddle linked in the PR and try to place a some new shapes and move them. You may want to update translateAnnotation to properly update annotation position, that is used on redraw when mouse is released or a new shape selected, I'm not sure.
I didn't notice the fiddles linked there at first.

[pawelfus]

Right, thanks!