Error handling is separated into SQL error vs everything else. SQL errors are gracefully trapped and reported in result object, all other exceptions are re-thrown for the application to handle.

When there is a SQL error the result object is populated with error details as follows:
result.ok will be false
result.error will have the error message returned by the server

With these changes there is no need for a separate error class and it is deprecated.

A new attribute raw_response is added to result class to help with troubleshooting.

* use pip3 since that's what homebrew prefers

* drop WHL file from distribution

* autoformatting, version bump, etc

Fix some typos and references and run a standard formatter
on the code base to fix up indentation issues.

* refactor error handling, handle some config errors better

If you hit an error like a missing hostport, you end up getting
two screenfulls or so of stack traces, which tells you almost
nothing, on a "wrong SSL version" message, which tells you something
incorrect.

We handle some errors more directly. However, the deeper issue
is that it's super annoying to both have to check for errors AND
have to catch exceptions. We treat errors as exceptions now; if
the server yields a non-200 status code, or we get an error message
even on a 200, we raise the error as an exception.

The "stoponerrors" feature is now the only real option, because
it doesn't actually make *sense* to set it to "no" outside of
test cases.

This dramatically simplifies a lot of code.

In the async case, we still raise a GroupException of any exceptions
encountered, unless there's none in which case we yield results.

Some tests are a bit stricter or more careful; for instance, if we
do two queries, we can just assert that we get exactly two responses,
not "two or more".

* use SSLContext for SSL connections

We started getting Ominous Warnings about directly specifying
capath/cafile to connections, so we create an SSL Context now.

As a result, we catch nonexistent cafile/capath during initial
client config, because we create the context once at startup.
Also, at the same time, move the URL computation to startup since
it never changes.

We need to distinguish "hostport unspecified" from "hostport
has default value", so the default value in the signature for
__init__ should be None; the actual default is set down below
inside the init function, after a check to make sure we are
okay with using a default.

set hostport default inside constructor, not in signature