Build System
* Require g++ v4.7 at least to not speak prehistorical C++.
* Require Boost 1.48 (for signal2 component).
+ * Java must be version 7 at least when activated.
* Tracing is now always enabled (no way to turn it out)
* Remove GTNetS. It was not working anyway.
* Move headers around to sort them out on installed systems: