Fixed #16594 -- Added wkt 3D support for GEOS geometries

This requires GEOS >= 3.3.0 to function properly. On previous
versions, the Z dimension will simply not appear in the wkt.
Disabled OpenLayers editing for 3D geometries (unsupported).
Fixed #19923 -- Display tracebacks for non-CommandError exceptions

By default, show tracebacks for management command errors when the
exception is not a CommandError.
Thanks Jacob Radford for the report.
Reformatted slightly openlayers.js
Fixed #9806 -- Allowed editing GeometryField with OpenLayersWidget

Thanks Paul Winkler for the initial patch.
Fixed #19171 -- Allowed coordinate transforms with custom SRIDs

Thanks reidpr at lanl.gov for the report.
Fixed BinaryField support on Oracle.
Fixed #20008 -- Removed trailing slash in Wikipedia link

Thanks senden9 at gmail.com for the report.
Fixed #20018: Added backtick to fix reference

Fixed #20018
Merge pull request #892 from JonLoy/ticket_20018

Fixed #20018: Added backtick to fix reference
Made (make|compile)messages check for availability of gettext commands.

Refs #19584.
Fixed #20019 -- Ensured HttpRequest.resolver_match always exists.

Obviously it isn't set until the URL is resolved.
Moved a warning in the 1.6 notes back to its expected location.
Made transaction.managed a no-op and deprecated it.

enter_transaction_management() was nearly always followed by managed().

In three places it wasn't, but they will all be refactored eventually.
The "forced" keyword argument avoids introducing behavior changes until
then.

This is mostly backwards-compatible, except, of course, for managed
itself. There's a minor difference in _enter_transaction_management:
the top self.transaction_state now contains the new 'managed' state
rather than the previous one. Django doesn't access
self.transaction_state in _enter_transaction_management.
Added an API to control database-level autocommit.
Separated autocommit and isolation level handling for PostgreSQL.

Autocommit cannot be manipulated independently from an open connection.
This commit introduces a minor change in behavior: entering transaction
management forces opening a databasse connection. This shouldn't be
backwards incompatible in any practical use case.
Enabled autocommit for PostgreSQL.

For users who didn't activate autocommit in their database options, this
is backwards-incompatible in "non-managed" aka "auto" transaction state.
This state now uses database-level autocommit instead of ORM-level
autocommit.

Also removed the uses_autocommit feature which lost its purpose.
Stopped flipping the uses_savepoints feature at runtime.
Expressed the dirty flag handling logic in terms of autocommit.
Added BaseDatabaseWrapper.ensure_connection.

This API is useful because autocommit cannot be managed without an open
connection.
Removed _enter/_leave_transaction_management.

The goal is to make all databases share a common, autocommit-based,
implementation.