Use jgrapht from Maven Central
The groupId of JNA has changed
Use a more recent version of gdms
Add orbisgis-nexus as parent for deployment
Remove provided scope
Don't use this system of distributionManagement
Stop building with Java 6
Use slf4j-simple in tests
Remove unneeded maven assembly plugin
Merge pull request #69 from agouge/update-pom

* Use jgrapht from Maven Central
* The groupId of JNA has changed
* Use a more recent version of gdms
* Add orbisgis-nexus as parent for deployment
* Remove provided scope
* Don't use this system of distributionManagement
* Stop building with Java 6
* Use slf4j-simple in tests
* Remove unneeded maven assembly plugin