Don't default a boolean prop to true

This seems to be a pretty common convention.

Avoid defaulting a boolean prop to true - if needed, flip the prop and default it to false instead. A true default means that you have to explicitly pass false, where as you can implicitly pass true in JSX.

// Multiple uploads is the default
allowMultiple={false} // bit ugly

allowSingle // more convenient

[[componentapi]] [[react]] [[reactapi]]