Pass package_type to IDatasetForm methods
Allow IDatasetForm to customize the edit template
Redirect to the dataset type view page after create or edit
Name all dataset type routes to allow URL generation

Routes have the form `dataset-type_action`, eg `harvest_source_read` or
`mydatasettype_edit`. This allows to build the url with url_for or
nav_named_link from the controllers or templates.
Fix vocabs test plugin
Register search page route for dataset types
Assign a default value to dataset type when dictizing

This makes search queries much easier
Index dataset type
Show relevant dataset types on the search pages

When visiting the search page of a custom dataset type (eg /<my-type>),
only datasets from this type are shown. On the main search page
(/dataset), only standard datasets are shown, unless the config option
`ckan.search.show_all_types` is set to True.
Call _setup_template_variables on search action

Also don't pass id on new action
Support alternative_url param on h.add/remove_url_param

This allows custom URLs like the ones from dataset types. Private
function _url_with_params was duplicated on helpers.
Call _setup_template_variables on read action
Use dataset type when generating URLs on the search page

This allows the Pager to generate URLs that point to the relevant
dataset type page, and not /dataset.
Use alternative_url on facet_list when genereating URLs

This allows dataset type pages to show their own facets and have links
pointing to the right direction.
Add a default value to package type field
Fix failing test due to default package type
Add db migration script for setting the default package type
Minor pep8 and pythonic changes
Add alternative_url to docstrings
[#233] Rename version due to conflict 064 -> 066