attempt at fixing #4.
Merge branch 'master' into issue4
updated Element with the iframe passed to the Page

(bug introduced as part of fix for #4)
first cut implementation of sections
improved section handling

* added support for sections with iframe context
* reduced frame switching
added .gitignore
second attempt at Section/Sections at page.

Simplified the implementation to use Section and Sections classes
that inject a 'root_fn' to the ElementGetter subclasses so that the
switch to the root element that defines a section is done more
predictably.

Reduced frame switching to as late as possible so unnecessary switches
don't occur.
Merge branch 'issue4'
Merge branch 'sections'

Conflicts:
	CONTRIBUTORS.rst
	doc/source/core.rst
	doc/source/development.rst
	doc/source/usage.rst