Improvements, cleanups and fixes

Dropdown

• the trigger can be a level 2 element
• the script now supports forms inside dropdown-menu
• made methods to be easily accessed
• now the script supports nested dropdowns

Collapse

• typo issue with aria attribute
• script methods are now public, also some fixes with calculating content height
• trigger wrong class manipulation
• accordions work excellent now

Carousel

• stop jumping when clicking on navigation items and carousel is animating

Modal

• Added ability to close current opened Modal when opening another
• stop jumping around when opening modals

Documentation

• typo issue with Button script
• added CDNJS link
• added demos for nested dropdowns and forms in dropdown