- Issue#17: Removed aria-label and deprecated `headerOpenLabel` & `headerCloseLabel`
 - Merged in PR from `@micmania1` for the correct spelling of _aria-labelledby_

 - Made NPM scripts bit nicer by calling each other. Also now compiling .css

 - Created the ability to have nested accordions. For this to happen I needed to change how a single accordion instance selected its headers & panels. Now the headers & panels selected are only 1 level deep.