Ability to match field names in a case sensitive manner

[mflorin]

Fixes #208
I've added a new configuration option and the associated code to be able to match map keys to field names case sensitively.
However, the first letter of struct field names is still compared case insensitively, to allow for the Go convention of publicly exported member names.

[mitchellh]

Thanks! I think the "ignore first character" is a bit odd... though I understand why you did it. Can you add a test for this?

[rpajak-solarwinds]

Thanks! I think the "ignore first character" is a bit odd... though I understand why you did it. Can you add a test for this?

I agree with @mitchellh .

|| strings.Title(mK) == fieldName should be removed. There should be another config to enable such matching.

@mitchellh any chances to have it soon? I want to use CaseSensitive together with ErrorUnused to have a very strict control during decoding.

[mflorin]

Yes, agreed, the logic is odd :) I think @rpajak-solarwinds 's idea to have a config would work. I'll make the necessary changes.

[mflorin]

@mitchellh , @rpajak-solarwinds I've added another config, TitleCaseInsensitive which works together with CaseSensitive. I've also added the tests. Let me know if that works better :) . Thanks.

[mitchellh]

I went with #250 since that supports any custom name matching logic. Sorry, but thank you!