Refactored.

Better conformance to PSR-1 and PSR-2 (without breaking B/C) ;
No more useless shallow copies of variables ;
Added total fuel inbound and outbound, deprecated TotalFuelUsed() which did not actually return total fuel but total inboud ;
More comprehensive commenting.
Fixed typo ; round fuel totals.
Merge pull request #4 from PierreLvx/master

Refactored.