Assertion definition generators.

Assertion definitions are methods that can be called directly on a page
or activity definition. These methods assert some aspect of the page or
activity. A method is generated by Dialect when an assertion definition
is encountered. That method will take some specific action based on the
type of assertion.

This is the start of the generator concept, where methods are generated
as part of Dialect's basic operation.
Element definition generators.

Element definitions are methods that can be called directly on a page
or activity definition. These methods assert a particular aspect of
interaction, either with a web page or a web activity (like an API
call). A method is generated by Dialect when an element definition
is encountered. That method will act to hook the underlying driver
library into the object represented by the element definition.

This is part of the generator concept, where methods are generated
as part of Dialect's basic operation.