MatchNamesWithUnderscores for Insert and Update

[pdcmoreira]

Insert and Update now take in consideration the DefaultTypeMap.MatchNamesWithUnderscores option and follow the model properties' PascalCase to table columns' snake_case convention. #515

[rhubley]

looks like there are several AppendColumnNameEqualsValue methods, you only fixed one to be columnName = @propertyName the rest are still columnName = @columnName

[pdcmoreira]

@rhubley I've changed several occurrences:
https://github.com/StackExchange/dapper-dot-net/pull/605/files

Can you please check? I might have missed something, but it's currently working for Insert and Update.

[NickCraver]

The general problem with supporting this is that functionality was one way (reading). To respect it writing it a breaking change and I'm not sure it's a good one. I'm going to close this out in favor of something else: I think we need a [Column] attribute to solve this in a very general way for everyone. There are quite a few issues in it and it makes a more direct and explicit solution available for all.

A link to the v2 planning should appear below this shortly for discussions which are very welcome. We want your input. If you don't agree with this general solution, ping me and I'll reopen this...just trying to consolidate a lot of activity for v2.