Update VolumesExtension.java

Added a functionality("UploadToImage") to upload a volume as an image to the image service.
Create VolumeForImageCreate.java

Java Class to create an input for sending json request
Create ImageFromVolume.java

Response for the uploadToImage functionality.
Update RoutersResource.java

Added functionality to detach router interface.
Merge pull request #84 from persistent-rCloud/master

Contributing to Openstack Java SDK (Nova-Volume, Quantum-router)