v2.1.0

Adding & moved some convenience methods to keep things nice and easy.

• Added all convenience methods from template builders to builders themselves
  • This should make template updates after initialization easier & cleaner
• Added a clear method to all template implementations
  • Removes all buttons from template
• Made fill method behavior consistent among all templates
  • Fills all slots that are currently empty
• Added convenience methods to relevant templates for making layouts from lists of buttons
  • These methods are appended with fromList
    • ie. ChestTemplate#row -> ChestTemplate#rowFromList
• Added InventoryHelper to assist in making player inventory changes that reflect in Gooey Pages
• Added more context methods to ButtonAction to see if slot clicked is in player inventory, and getting the clicked slot in inventory template