update the integration class
Merge pull request #2224 from lambday/develop

reduced accuracy in kernel row_col_wise_sum_block_with_diag unit-test to prevent buildbot failure
change to BSD
added opencv as the optional dependency and a basic test in tests/integration/opencv.
added flags for opencv integration in CMakeLists.txt.
shortened the flag name for OpenCV integration
opencv integration test cleaned_.
removed system include for OpenCV from CMakeLists.txt
cleaned whitespaces.
Merge pull request #2221 from kislayabhi/develop

added opencv as the optional dependency.
Relaxing function check in valgrind suppression file: libhdf5 changed function names.
Merge pull request #2227 from tklein23/develop

Relaxing function check in valgrind suppression file for libhdf5
Forgot to delete RefCount object when done.
Merge pull request #2228 from tklein23/fix_refcount_unittest_leak

Forgot to delete RefCount object (in unittest) when done
add contributions to readme
Features added for handling missing values and tree pruning
Merge pull request #2216 from yorkerlin/yorker-integration

update the integration class
Merge pull request #2226 from mazumdarparijat/C45

Add feature for tree pruning and handling missing values in C4.5
NEWS update and return type changed for prune_tree method
CART class structure added w/o implementation