Update to 1.6.0 after changes suggested by Ben.
Merge branch 'develop' into TG-559-update-to-1.6.0

Conflicts:
	acceptance/pom.xml
	core/pom.xml
	core/src/main/java/com/novoda/imageloader/core/model/ImageTagFactory.java
	demo/pom.xml
	pom.xml
Merge pull request #139 from novoda/TG-559-update-to-1.6.0

Update to 1.6.0 after changes suggested by Ben.