Add support for externally registered factories

Useful when you can't, or don't want to modify the
classes you're hydrating.
Reduce excessive info level logging
Migrate to modules
Guava Optional support
Fix contributor formatting
Adding myself as a contributor
Swap log4j for slf4j
Add Travis build file
Ignore Pdm4PojoUnitTest, broken on jdk7

Issue: https://github.com/mtedone/podam/issues/25
Prrof: https://travis-ci.org/astubbs/podam