New overload so this isn't a breaking change. We can collapse down in v2.0 (including the Impl method).

Add dynamic overloads for:
- QueryFirstAsync
- QueryFirstOrDefaultAsync
- QuerySingleAsync
- QuerySingleOrDefaultAsync

This may change a lot in 2.x, but many people asking for them now so here they are. Unit tests also fixed for QuerySingleOrDefaultAsync.

Note: this builds on the netstandard2 branch because of the xUnit changes to go with VS 2017 15.3.

.NET Core 2 SDK is on the base Appveyor image now

This uses the new non-parallel-at-the-end I added to xUnit in https://github.com/xunit/xunit/pull/1411 This way we can run any global test that are other-test-unfriendly much more easily.

* Enable SqlDataRecord TVPs on netstandard1.3.
* Update netstandard2.0 SqlClient references to Preview 2.
* Skip TransactionScope tests for netcoreapp2.0.
- According to https://github.com/dotnet/corefx/issues/12534, ambient transaction enlistment is not included with .net core 2.0.
* Update references in Dapper.StrongName.
* Disable parallel test run to stabilize flaky type handler tests.
* Disable parallel test run by assembly attribute.
* Move Issue461 tests to TypeHandlerTests.
* Group type handler tests in a collection, re-enable parallelization.
- Being part of the same collection, type handler tests will run sequentially. All other tests can run in parallel.
* Move tests relying on query cache & type maps to a separate collection.

This reverts commit e7ad0874.

Markdown tables instead of html
“Can be faster” in correct row

OperationsPerInvoke is an informational, not instructional property.
What we actually want is the UnrollFactor. Moved into the job definition
to simplify things.

* Fix for PostgresAdapter in SqlMapperExtensions.Async. Copied same line of code from SqlMapperExtensions to fix RuntimeBinderException on InsertAsync
* Cleanup

Use an HTTPS link where possible.
Fix 404 for performance tests.

* Don't create the connection in Dispose: this avoids creating a SQLConnection simply to Dispose it.
* Run MySQL tests against the open MySqlConnection: 'connection' is a protected variable in the TestBase class that is a SQL Server connection, not a MySQL connection.
* Skip broken MySQL tests: as per issue #295, setting "AllowZeroDateTime=True" in the connection string causes an InvalidCastException in SqlMapper.

This adds a netstandard2.0 build to Dapper (and StrongName until v2),
adds a netstandard2.0 test lineup, restores most functionality (except
UDTs for SQL, e.g. .UdtTypeName isn't in netstandard2), and also breaks
things not actually implemented or implemented correctly in
netstandard2.0. Pushing this up so we can work through these with the
.NET teams.

Several things are still broken here (and fail tests):
- Parameter decimal values (not filed yet)
- DataTables as parameters
(https://github.com/dotnet/corefx/issues/19708)
- .GetSchemaTable() (not yet filed, implementation is completely missing
from SqlDataReader in CoreFX)

While the compile is clean, the above are runtime issues.
`SqlParameter.UdtTypeName` is a separate issue, that one just wasn't in
`netstandard2.0` at all...so we can't support UDTs there until it is.
See https://github.com/dotnet/corefx/issues/17126 for details.

More cleanup to do (removing Type column next), but getting to some very
usable output now.

This is based on BenchmarkDotNet (while preserving the legacy format
with minor improvements as well - legacy runs much faster). See #666 for
details. Not an ominus number at all.

Note: this code will get a bit simpler with BenchmarkDotNet categories,
see https://github.com/dotnet/BenchmarkDotNet/issues/248 for details.

It's indeed broken on their end. We should consider switching providers,
e.g. https://github.com/mysql-net/MySqlConnector/