[#790] Tutorial for custom fields in packages
[#790] add custom fields tutorial to extensions index
[#790] clean up formatting
[#790] resource customization tutorial

also added resource example to idataset form example
[#790] add tag-vocabularies to custom-fields tutorial
[#790] fix titles to match docs style guidelines
[#790] custom fields tutorial

move source for tutorial into it's own files
[#790] custom fields tutorial

* Add tests to example_idatasetform plugin.
* Split out source from tutorial into plugins so they can be tested
* Use sphinx referencing
* Add section on validators and conveters
* Minor rewrites, fix titles, etc.
[#790] undo doc subproject commits
[#790] remove unused plugin version
[#790] pep8, fix tests by preventing plugins from loading during import
[#790] IDatasetForm tutorial cleanups
[#790] IDatasetForm tutorial: add dataset search page sorting
[#790] Add IDatasetForm search template
[#790] idatasetform tutorial cleanups
[#790] idatasetform tutorial cleanups
[#790] idatasetform tutorial cleanups
[#790] save pylons config prior to tests, restore config in teardown

The plugin implements IConfigurer which adds a directory to the
templates. This clashes with the tests for the multilingual extension
that are running off the legacy templates. Having the
package/search.html template here causes the clash.

Saving and restoring the config means the multilingual tests will not
pickup and templates from this plugin.
[#790] add test for search ordering by custom fields
Merge branch 'master' into 790-idatasetform-tutorial

Conflicts:
	ckan/new_tests/helpers.py