Add test DiscriminatedUnionWithMultiMapping

DiscriminatedUnionWithMultiMapping - test for check correct MultiMapping (splitOn) functionality with discriminated row parser.

Update Readme.md

Note: there's still a 1.0.0 vs 1.1.0 quirk here - digging.

Readme: Better explanation for multi mapping

GridReader.IsConsumed wouldn't be true

Non-greedy match for comments regex

Fixes #436, #280
My editor has also normalized a few line endings to LF like 99% of the
file was.

Update readme.md

Missed second bracket in ID example

Make CommandBehavior optimizations more configurable

Make CommandBehavior more configurable; default to SingleRow=allowed,SingleResult=disallowed - but expose options; this fixes issues like #563 automatically, and allows the performance aspect  of #554 to be fixed via a global setting

Add CommandDefinitions versions for async Query API

Add CommannDefinition versions of Query(First,FirstOrDefault,Single,SingleOrDefault)Async and a few unit tests for them

Operate on db records instead of files.

Fix #573 - OrWhere yielding AndWhere statement