add rank and wmw test source files (diverged from myCtutorial)
C code added; now qsort does not work. Why
C functions for R
remove print functions for array values
(1) remove print functions (2)compDRank works now correctly. See comments
remove unnecessary debugging functions
add testing function in R
dArray and iArray are not used here since we directly with arrays
DRank uses pointer to double value instead of copying the value
debug huge memory consumption: dynamically allocated arrays (list->list, which is a *DRank) must be freed. Before only its members and its parent structure is freed
do_wmw_test has been refactored into wmw_test, which makes the function running much faster (<60s for 2000 samples in a single core!)
debug memory leak: *array in a struct must be explicitly freed once it is not used anymore, between the step of freeing all its members and the step of freeing its struct