some fixes and improvements to the crafting UI

[UmbarPantera]

input field of the number wheel:

• remove all decorators before dealing with the user input
• place the cursor next to the number, if it is in front/behind the decorator, so you no longer have to move the cursor to this position manually to be able to edit the number
• create an own function for input validation and use its result for some basic error messages, so the user gets a better idea what's going wrong
• make it possible to add some custom styles to an alert message, if you display it and use this to make error messages red

Limit the input field for a custom item name to 28 chars, because it will get cut off at this point anyway and add an error message, if you try to enter more than 28 chars.