Distribution EOLE

Merge inbox-rendering-recursion-1208-5

Author: exarkun
Reviewer: glyph
Fixes #1208

Introduce the nevow.page module which primarily exposes one new class (for
the moment): Element. Element is a replacement for nevow.rend.Fragment
and does not expose the context to application code during the render phase,
or at any other time. Athena's remote method decorator has been
generalized and is now also used to expose render methods on the Element
class, rather than the conventional render_ prefix.

Athena has gained LiveElement which is just like LiveFragment except
it substitutes Element behavior in place of Fragment behavior. Athena
also no longer supports the allowedMethods dictionary: expose is the
only API for marking methods as remotely callable.

Mantissa and Quotient have been updated to use these new APIs in several
locations. LiveForm is now an Element rather than a Fragment. A new
class for backwards compatibility has been added, LiveFormFragment,
for applications which cannot easily migrate to the requirements of
Element.

Test coverage for Axiom's transacted decorator now exists. Several
bugs in that function have also been fixed. Extensive test coverage
for the PySQLite2 and APSW backends for Axiom has also been added and
a bug in the timeout support in the PySQLite2 backend fixed. APSW
was previously very broken and remains somewhat so, though with tests
pointing out what exactly is broken. Timeouts now raise a specific
exception, axiom.errors.TimeoutError, rather than whatever the
underlying system feels like raising.