Autoloader should return true if it can handle the class so other registered autoloader don't execute.
require is faster than require_once and should be safe to use since the autoloader won't run if the class already exists

This allows to quickly check if a variable is empty but keeps strings
and numbers evaluating to zero.

Sorting by the sort number is too confusing since those are assigned
independently by different authors

You now can add labels that don't wrap around inputs, but you have to
ensure IDs are properly assigned yourself.

The Label class has been renamed to LabelElement to reflect the naming
scheme of the other elements.

This event handles both known core types and unknown types as default

edit translation of the user 青子守歌

re-add PR #470 again.