Add list and List definitions from the prelude

The StandardPrelude.methods inheritance only exposes methods defined
internally, not those actually defined in the StandardPrelude Grace
module. As such, the collections definitions are not exported by
objectdraw. This changes adds the list class and List type to the
objectdraw module.
Use page* instead of client* for event points

The calculation of event points used the clientX and clientY properties
of the event object, which is relative to the top-left corner of the
client, which means it did not take into account scrolling when
comparing it against the element's offset values. Now the calculation
uses pageX and pageY, will will provide the correct values if the page
is scrolled.