Refactor to add an rzSliderOptions attribute

As reported in #174

As explained in #172 .

As discussed in #161

This is to ease to use of non linear/number steps. As suggested in #163

As mentioned in #162

Implement the solution described in #159 .

Refactor the slider architecture. Add a rzSliderOptions that handle all the options except model, high and rzSliderTplUrl

Hide combined label when show-ticks-value=true.

Update floor label so that it hides correctly when using single slider.

Closes #154.

Configurable update interval