FR: add label rotation

[timelyportfolio]

For your info, this seems to be a hack (somewhat) as there currently already label rotation functionality in the d3.parcoords.js.

See: https://github.com/syntagmatic/parallel-coordinates/blob/master/d3.parcoords.js#L604

(and the __.dimensionTitleRotation) property which is accessible trough a getter/setter.

Admittedly, discover ability of this functionality is not that great =:D

[talgalili]

Cool, could you add it as a parameter to the function?

[timelyportfolio]

yes, will do; track with #11

[DataStrategist]

+1 for this feature. Thanks @timelyportfolio this package looks great, but I kind of need to be able to rotate the labels. Any chance we can get an example on how to accomplish this via getter/setter if pushing as a parameter is too much work? Thanks again!