Allow custom casing on inferred enum graph types

[freakingawesome]

The default behavior of EnumGraphType converts the enum values to uppercase. This commit allows you to specify a custom behavior for changing case.

[joemcbride]

This appears to have a valid failing test, can you take a look?

[freakingawesome]

Yea, that's an odd failure. I haven't been able to reproduce it locally or make any sense of how my minor change could have caused the failure. I'm merging latest from master to trigger another build and will see what happens.

[freakingawesome]

Another failed build - but this time it's failing on what looks like nuget trying to create a an invalid version string.

[freakingawesome]

I think that latest nuget failure is caused by the / character in my branch name. I could close this and open up a new PR against a more appropriate branch name to see if that fixes it, if you think that would be beneficial.

[joemcbride]

No that's fine, that is a known issue in the build script currently.