Add a DeserializerFeature that enables Case Insensitivity

[mressler]

Discussion here: http://jackson-users.ning.com/forum/topics/case-insensitive-properties

Somehow I found that location before I found this GitHub repo. I plan on implementing this as a DeserializationFeature and submitting a pull request. I'm happy to take any pointers or discussion in the comments here on GitHub.

[cowtowncoder]

Always happy to get implementation of new features! The main concern really is with complexity of BeanDeserializer, but if addition can be achieved without seriously adding to complexity, it would be great. And I think many users would find such feature useful.