Fixing centering matrix bug - found by coverity CID 25867
Fix memory problem from coverity CID 26288
Missing break statement found with coverity CID 26157
Uninitialized Gmax_init (dead code) found by coverity CID 25869
Removing centering-matrix instead of fixing it.
Merge pull request #2144 from tklein23/coverity_error_cid_25867

Fixing centering matrix bug - found by coverity CID 25867
Merge pull request #2156 from tklein23/coverity_errors

Coverity errors: CIDs 26288, 26157, 25869
fixed the file path issue
Merge remote-tracking branch 'upstream/develop' into develop
update the upstream
Fix CustomKernel-unittest bug.
Fixed Kernel.cpp Warning.
add the description
Merge pull request #2164 from pl8787/indexfeatures

Fix CustomKernel-unittest bug.
Merge pull request #2161 from yorkerlin/develop

fixed the file path issue for the variational example
added PCA notebook to the NEWS.
Merge pull request #2165 from kislayabhi/develop

added PCA notebook to the NEWS.
memory leak fixed
Merge pull request #2166 from mazumdarparijat/decision_tree

memory leak fixed
add to news