PSR-2 in tests

[iwankgb]

Following changes have been applied:

• each class lives in its own file (PSR-1);
• each class has a namespace defined (PSR-1);
• lines longer then 120 lines have been broken into multiple lines (PSR-2);
• ExampleTest class is renamed to FullApplicationTest (PSR-4 - yes, I know it is not part of PSR-2 but it's close enough to me).

Tests had to be modified a bit and TestController file moved to another location to accommodate changes listed above.

Some additional issues have been identiefied:

• Laravel\Lumen\Application::handle() method is beind used in tests while in real world Laravel\Lumen\Application::run() will be used;

[taylorotwell]

See comment on previous PR.