Remove prepareToSimpleStmt

It doesn't appear to be serving any purpose, so remove it.
Cache time.Location for Performance

Previously a new time.FixedZone was created for every single time
fetched from the database. This is an immutable structure that is
somewhat expensive to create and so should be cached. Benchmarks
indicate slightly under a 20% speed improvement with a reduction in
allocs from 5 to 2 and a reduction in memory allocated from 213 bytes to
66.
Add Benjamin Heatwole to the list of contributors
Tolerate CommandComplete messages before the data in Simple Query

Commit 1e2ccf84caca692327146254602c580cbf inadvertently broke the case
where one or more CommandComplete messages were received before an
actual result set, as reported in #282 by rylanhalteman.  Revert to the
old behaviour of tolerating any number of CommandComplete messages
before the actual data is received.
Skip test case for issue 282 on Go 1.0

It unfortunately doesn't know about the Queryer interface :-(
Handle EmptyQueryResponses correctly

Like hochhaus noted in #284, we previously didn't handle
EmptyQueryResponses from the server correctly.  Fix by treating them as
a 0-row, 0-column result set.
Fix incorrect parsing of negative time zones
Fix formatting verbs in test error message
Correctly encode time zones with seconds

The previously used RFC3339Nano format to encode times does not take
seconds into account for time zones. This commit fixes that by appending
the time zone seconds to the formatted time, but only if it's non-zero.

Fixes #286
Add Joël Stemmer to the list of contributors
Fix missing call to processReadyForQuery

There was still one place which didn't update the transaction status
indicator based on the ReadyForQuery message.  Prior to this fix, a call
to Commit might have sometimes erroneously complained about the command
tag being ROLLBACK instead of returning the correct error, "Could not
complete operation in a failed transaction".  Though such an application
would have had to ignore a failed query in the first place, which would
explain the lack of bug reports.

Found while investigating a report from Eric Chlebek in #225, though I
can't come up with a scenario where his problem would have been caused
by this.
Merge branch 'master' into open_no_errbadconn