Remove some unnecessary imports.
Fixed wrong link to dropwizard-extra-core

Was pointing to 'common' instead of 'core'.
Merge pull request #14 from tedyoung/patch-1

Fixed wrong link to dropwizard-extra-core in README
Add Scala enrichments for jDBI transaction lambdas

Can now use transactions with Scala function literals:

```scala

trait MyDAO extends Transactional[MyDAO] {
  @SqlQuery("SELECT a FROM my_table WHERE b = :b")
  def find(@BindParam("b") id: Int): Int

  @SqlQuery("INSERT INTO my_table (a, b) VALUES(:a, :b)")
  def add(@BindParam("a") a: Int, @BindParam("b") b: Int)
}

val dbi: DBI
val dao = dbi.daoFor[MyDAO]

// raw transactional query
val inserted = dbi.inTransaction { handle =>
  handle.execute("CREATE TABLE my_table")
  handle.execute("INSERT INTO my_table (a, b) VALUES (1, 2)")
  handle.select("SELECT a, b FROM my_table")
}

// transactional DAO
val b: Int = dao.inTransaction { obj =>
  obj.add(5, 7)
  obj.find(7)
}
```
Merge branch 'develop' into feature/scala-support
Remove useless DBI wrapper methods

There's no situation where you'd want to have a transaction that
accepted the transaction status (which is optional), but not the handle
(which is mandatory).
Fix ScalaService extending Service

`Service` has been renamed `Application` upstream.