Remove better_errors config require from rake task

The rake task doesn't load Sinatra so it doesn't have `configure`. Plus,
since this is a rake task to be run from the console, having an HTML
error page isn't actually very useful.
Merge pull request #40 from alphagov/remove-better-errors-config-from-rake-task

Remove better_errors config require from rake task
Allow schema to set elasticsearch type and index

Sometimes we have date fields. Sometimes we have fields that we want to
analyze (and therefore include in _all for keyword matching).
Don't expand values for date fields

Now that we support date facets with allowed values we want to not
expand the values into a value/label pair.

We'll move to having date facets as proper types at some point with
before and after text inputs, rather than piggy-backing on the
multi-select functionality.
Add date_of_occurrence to AAIB report schema

Uses a multi-select facet for now with every year of imported report data
included in the list. The oldest date of occurrence in the imported is
1958-02-06.
Improve regex used for segregating date criteria

Rather than only treating fields that end in `_date` as a date field,
match any field with `date` in it, either at the edge of the word or
surrounded by underscores, eg:

- date_of_occurrence
- opened_date
- some_date_thing