Performance tests

This adds performance tests for a basic SELECT mapping query against Hibernate and hand-coded ResultSets.

This also moves the readme to markdown.

If this is headed in the right direction, I think we should definitely add the following as well:
* [Apache DbUtils](http://commons.apache.org/proper/commons-dbutils/)
* [Spring JdbcTemplate](http://docs.spring.io/spring/docs/4.0.0.RELEASE/spring-framework-reference/html/jdbc.html#jdbc-core)
* [MyBatis](http://mybatis.github.io/mybatis-3/)
* [JDBI](http://jdbi.org/)
* [persism](http://sourceforge.net/p/persism/wiki/Manual/)

We could add more down the road, like:
* [EBean](http://www.avaje.org/)
* [JdbcHelper](https://code.google.com/p/jdbc-helper/)
* [Yank](https://github.com/timmolter/Yank)
* [OrmLite](http://ormlite.com/)
* [jOOQ](http://www.jooq.org)
* [JaQu](http://www.h2database.com/html/jaqu.html)
* [iciql](http://iciql.com/)