Improving encapsulation of the project

Improving code encapsulation for each of the packages

• Lou-Anne -> gtd-server-core, gtd-server-rmi, gtd-server-thrift
• Camille -> gtd-server-main
• Thomas -> gtd-server-gui
• Sofiane -> gtd-server-persistent

gtd-server-main

No fields to encapsulate have been found in this package. However, the Java coding convention will be respected in the rest of project