Support for dynamic heights and paddings

[lubomirblazekcz]

Description of Proposed Changes

Hey @alexmacarthur I've resolved the problems when height is dynamicly changed, I've changed fill from forwards to backwards, this way the style properties will reset upon animation, so there are no more problems with height. Also added new option cache, if someone expect the height to change in the future it should be disabled. To be honest caching the height isn't the best approach, height can change anytime, eg. responsive design. Maybe you should reconsider if not to remove the caching instead?

I've also resolved the gotha with the padding as bonus https://github.com/alexmacarthur/slide-element#gotchas but the box-sizing: border-box must be use for this to work.

Related Issue (if applicable)

#19

Testing Steps

Didn't add tests or changed the version, leaving that up to you :)

[alexmacarthur]

Thanks for this, @lubomirblazekcz!! Looks great, and I appreciate the padding fix too. I'm gonna close this + bring your work to another PR where I've made a couple other adjustments and fixed tests.