feat(translate): Pass a label string as third arg to the translate function to differentiate the lab

Closes #252

Thanks to this, we can now pass html-formated content in the translate function

Closes #251

Closes #245

feat(enforceStep): Add an enforceStep option (defaults to true)

feat(selectionBar): Add a showSelectionBarFromValue

feat(range): Add a noSwitching value to prevent switching min/max

I was not accepting sliders with floor=7, ceil=7 and step=10 that are actually valid.

Closes #234

The minimum range authorized on the slider.

Closes #231

onStart should be called before any update so it should not be wrapped inside a .

perf(initialisation): Remove the timeout call in init.

Closes #220

perf(): Remove $timeout call inside onChange event

When the callback run while changing the slider takes a certain amount of time (~50 ms or more), the
 inside onChange can stall resulting in many changes lost along the way while it catches up.
Removing seems to have no visible side effects. It might be possible that this is due to
scope.() being called right before callOnChange(), so the model is updated anyway (see in
applyModel)

feat(selectionBar): Add a showSelectionBarEnd option

as requested in #213

Set to true to only bind events on slider handles.