Fire on_fetched for ?version=all
Test on_fetched events for versions
Add warning about ?version=diffs on_fetched events
Fire on_fetched events for ?version=all requests
Merge branch 'jenmontes-version_all_on_fetched' into develop
Sphinx formatting
Customizable query parameters.

QUERY_WHERE allows to customize the 'where' query parameter.
QUERY_SORT allows to customize the 'sort' query parameter.
QUERY_PAGE allows to customize the 'page' query parameter.
QUERY_MAX_RESULTS allows to customize the 'max_results' query parameter.
QUERY_PROJECTION allows to customize the 'projection' query parameter.
QUERY_EMBEDDED allows to customize the 'embedded' query parameter.

Use case:
https://stackoverflow.com/questions/26375341/in-python-eve-how-can-i-honor-size-query-parameter-as-an-alias-for-max-resul
py 1.4.25 added to dev-requirements
Read-only fields ignored on write if value doesn't change.

When some fields are set to read-only, it becomes very difficult to use the API
because the client has to ensure those fields are removed from the object
before to send it back for editing via PATCH. When new read-only
fields are introduced, it has good chance to break every clients already using
the API.

This fix ignores submitted read-only fields in PATCH if the submitted values
aren't changed compared to the stored document.

Closes #479