Update documentation, mention "playjongo.test-uri"
Allow to configure a jongo mapper factory for customized jongo mapper.

This adds the optional "playjongo.mapperfactory" configuration which accepts
the name of a class implementing uk.co.panaxiom.playjongo.JongoMapperFactory.
The factory class must also provide a default constructor.
Add JongoScalaMapperFactory for jongo/jackson scala support.

Uses need to add
  `"com.fasterxml.jackson.module" %% "jackson-module-scala" % "2.2.1"`
to their build appDependencies and
  `playjongo.mapperfactory="uk.co.panaxiom.playjongo.JongoScalaMapperFactory"`
to application.conf.
Allow to change the default write concern for mongodb.

Add `playjongo.defaultWriteConcern` to application.conf with values
from the java drivers WriteConcern enumeration.
Merge pull request #17 from magro/configure-test-uri

Update documentation, mention "playjongo.test-uri"
Merge
Merge branch 'default-write-concern' of git://github.com/magro/play-jongo into magro-default-write-concern

Conflicts:
	README.md
	app/uk/co/panaxiom/playjongo/PlayJongo.java
Fix compilation error after merge issues.
Add findbugs
Add unit tests for configuration.

The authentication is not tested as this would involve communication with
mongodb and thus we would need to integrate s.th. like a mongo mock - too
much effort for this.
Add ASL2 license file, closes issue #18
Mention License in README
Add build status widget.
Change jenkins build status icon