Refactored gis/spatialite connection initialization

The connection state is now initialized in get_new_connection().
Refs #19274.
Removed duplicate opts.pk_index() method
Fixed #19370 -- Made date filter properly handle midnight value
Added 1.5 beta release notes.
Fixed a couple of typos in the 1.5 (and beta) release notes.
Fixed #19352 - Added an example in the QuerySet docs.

Thanks colinkeenan for the suggestion.
Fixed #19239 - Added examples for generic date views

Thank-you Daniel Greenfeld and Scott Nixon.
Fixed #19374 -- Typo in docs/ref/models/instances.txt.
Merge pull request #559 from tail/ticket_19374

Fixed #19374 -- Typo in docs/ref/models/instances.txt.
Typo in the 1.5 release notes
Fixed #14694 -- Made ``defer()`` work with reverse relations

Reverse o2o fields are now usable with defer.
Fixed #19366 -- Prevented GEOSIndexError when comparing geometries

Thanks Craig de Stigter for the report and collaboration on the
patch.
Converted a couple of assertEquals -> assertEqual
Fixed two docstring/comment typos.
Merge pull request #560 from brutasse/fix/1.5-typos

Fixed typo in the 1.5* release notes. Thanks brutasse.
Fixed #19356 -- Increased session key entropy.
Fixed #19354 -- Do not assume usermodel.pk == usermodel.id

Thanks markteisman at hotmail.com for the report.
Fixed #19400 - Typo in docs/topics/auth.txt
Added missing custom user skip decorator

PermissionDeniedBackendTest references User model.
Fixed #19349 -- Fixed re-rendering of ReadOnlyPasswordHashWidget

Thanks tim.bowden at mapforge.com.au for the report, Andreas Hug
for the patch and Anton Baklanov for the review.