CEC 2013 benchmark functions. Refactor test code.

Notes:
* GPU and CPU runs now belong to different test classes, together with
their resources.
* New Global environment for tests, defining the common resources.
Moved CPU code out of common class.

TODO:
* CPU Prn generator is causing problems when using multiple threads. CPU
  GA breaks when using OpenMP parallelize the crossover operator.
* CUDA PSO velocity vector, must be filled using a kernel call. Possible
  bug due to memory corruption when using cudaMemset to set float values.
Fix for filling CUDA array. OpenMP clauses for CPU loops.
Merge pull request #2 from rdelcueto/testing

CPU/GPU Test resources separation. OpenMP parallelization for CPU code. CEC 2013 benchmark functions.