Fixed 'animate' issue.

[marttop]

Description

#937 Fixing this issue by not recreating the stylesheet.

#1391 I created another pull request (It's for sure not the proper way to do but I still struggle a lot with git) and followed @adumesny's advices :

• I don't check anymore for existing styles because I could prevent _max from being reset every time
  For cellHeigh() and margin(), on method _updateStyles I added a boolean parameter 'doForceUpdate' witch is set to true only when called from cellHeight() or margin(). In that case I reset the stylesheet.
• I tried my best to respect your coding style as you asked.
• I tried to remove the _initStyles method and add it to _updateStyles but kept on breaking the behaviour so I let you do it... It seems I don't know enough on the component to do so.

Checklist

• Created tests which fail without the change (if possible)
• All tests passing (yarn test)
• Extended the README / documentation, if necessary

[adumesny]

thanks for taking a second look. I think I want to re-write this all thing rather than try to patch what's there... but I need to understand all corner cases first. We also should delete the style when destroy() happens (which we don't) so we need a separate removeStyle() method that will also reset the max info structure...

Probably best to let me do it at this point. I'm tied this weekend but might get to it middle of next week.

[marttop]

I understand that you want to rewrite it, but just in case, this at least fixes the bug temporarily.

[adumesny]

thank you for fix suggestion! I ended up re-writing that code instead #1395 AND default to animate since SO much nicer (I even didn't know about it).