Allow perPage to be a float value

[adambichler]

Allowing the "perPage" value to be a float would allow the developer to show a part of the next slide to tell the user that there is more content. Currently the dev has to use the "padding" option, which adds a padding to the right (i.e). The issue with that is, when the last slide is shown, the previous slides are not visible any more - and there is a padding to the right.

The dev could use a padding to the left AND right, but then the slides would be centered, which is not great if the slider is not looped (means padding on the left side = first slide).

swiper.js has implemented a float value for the "perPage" option, so maybe add a similar behaviour?

Thanks!