refactored css and js

[herosnowman]

• replaced style='display:none' with 'display--none' class, in order to keep css easily editable since style attribute can't be overriden by classes when needed
• replaced all style.display with setDisplay() function
• added setClass() function for adding/removing css classes
• simplified setting display value. display 'initial' and 'block' are the same in case of div elements, and by default div elements are display 'block'. which means js only has to hide the div by adding display--none class and show it by removing 'display--none' class. in case of the 'flashButton' the logic still works, since it was previously shown by setting display 'initial' and by removing the 'display--none'

[pkendall64]

Awesome, thanks.

[pkendall64]

Did you try them? I've been having a look and it's completely broken everything! I'll revert master back to where it was before this was committed and you can resubmit when it's working.