Added automatic @ingroup directives for non-local functions

For a function of the form foo.bar.baz(...) the directive @ingroup foo
is prepended to the function declaration. No check is made as to whether
the group actually exist, but if it does not the directive is a no-op.

This only handles a single level of grouping.
Automatic docuentation of torch classes

Now instances of torch.class('foo.Bar') will result in insertion of

	@class Bar
	@memberof foo

in the output stream. A torch class can thus be documented directly, and
the documentation will be added to the class, and the class to the
namespace.
Only explicitly documentated variables include

Use @var to document variables. This solves issues where all assignments
(not just declarations) are documented.