Implemented F-Race for population

Signed-off-by: Dario Izzo <dario.izzo@gmail.com>
Addressed all points in the code review

Signed-off-by: Dario Izzo <dario.izzo@gmail.com>
code review 2nd iteration
Small fix on test_racing and docs
Fixed the sphinx documentation for decompose
Fixed the default problem of decompose to zdt1(2) (instead of zdt1(1))
Updated the new name of the problem from decomposition to decompose
improved test logs
Fixed zdt1 to check the problem size is at least 2
Fixed sphinx documentation on USAGE case for rotated, shifted, normalized and death penalty problems
Merge branch 'development' of ssh://pagmo.git.code.sf.net/p/pagmo/code into development
logging the weight vector
Bug fix in race_pop
population can now be seeded. race tests are now not fragile
Restored all test cases
doxygen improved
Implemented F-Race for population

Signed-off-by: Dario Izzo <dario.izzo@gmail.com>
Addressed all points in the code review

Signed-off-by: Dario Izzo <dario.izzo@gmail.com>
code review 2nd iteration
Small fix on test_racing and docs
improved test logs
Bug fix in race_pop
population can now be seeded. race tests are now not fragile