v0.4.3 - infer enhancements

This release makes it easier to infer schemas:

1. When infer* receives a lazy seq, it acts as if it's individual documents. This makes great sense when you want to generate a common schema for eg. all the data files contained in a folder.
2. Better error messages when finding nil values (suggest :nullable true)

The underlying Java library has also been updated.

Full Changelog: v0.4.2...v0.4.3