imgproc module unit test failure on MSVC2015 release builds

[plstcharles]

Building the framework on Windows using MSVC2015 and CUDA may cause a unit test to fail in release mode. The test in question:

65>        Start 17: litiv_utest_imgproc_global
65>  17/30 Test #17: litiv_utest_imgproc_global .......***Failed    9.13 sec
65>  [----------] 1 test from descriptor_affinity
65>  [ RUN      ] descriptor_affinity.regression_L2_sc
65>E:\develop\litiv\modules\imgproc\test\global.cpp(358): error : Expected: oAffMap(i,j,k)
65>        Which is: -1
65>  To be equal to: oAffMapTmp(i,j,k)
65>        Which is: 0
65>  ijk=[0,0,0]
65>  [  FAILED  ] descriptor_affinity.regression_L2_sc (475 ms)
65>  [----------] 1 test from descriptor_affinity (475 ms total)

Will have to investigate further later on.