Add class name to error message of static method lookup failure.

Summary: This will be useful when we add support for typechecking static method
lookups on objects, since the type of the object may not be immediately
obvious.

Reviewed By: @elgenie

Differential Revision: D1568867
Replace boost::{next,prior} with std::{next,prev}

Summary: They're the same thing, but one is in the standard lib.

Reviewed By: @jdelong

Differential Revision: D1573137