Use the "official" language name in the code header

[ggrossetie]

• csharp -> C#
• xml -> XML
• csv -> CSV
• js -> JavaScript
• javascript -> JavaScript

If there's no explicit mapping, we should probably capitalize the first letter:

• java -> Java
• scala -> Scala
• python -> Python
• groovy -> Groovy
• cypher -> Cypher

I think conf and properties should remain in lowercase since they only refer to the file extension. Thoughts?

//cc @ElaineRosenberg