Question plugins

[Meorge]

There are several question types that would be nice to have available:

• Hexadecimal number/value entry
• Binary number/value entry
• Short answer with regex verification
• Select location on image
• Organize items into a specific order

However, I recognize some of these (especially things like hex/binary) are specialized and wouldn't be required by many classes.

Being able to create and add question type plugins would help with this. People who need a specific question type for their subject could implement it without needing to modify Qlicker's main code or fill others' screens with unnecessary question types.