Add valgrind suppression file when running ctest memcheck
add strange leaking errors of libxml2 to the suppression file
add randomized unit-tests for IO, increase precision for ASCII writers
fix latex error in doxygen
Merge pull request #1679 from gsomix/feature/protobuf

Unit-tests for IO
Fix leaking classes related issue #1477
Revert changes in VwRegressor.cpp
fix a small memleak in SGObject.ref_unref unit test
Fix typo in tests/integration/python_modular/CMakeLists.txt
this should fix issue #1661
reduce number of x-validation repeats and number of parameter combinations in grid-search
decreased number of iterations to make test run faster
Merge pull request #1681 from karlnapf/develop

speed ups for tests
removed notebooks since there will be a more complete one soon
reduced size and accuracy for speeding up unit-tests
minor documentation correction
Merge pull request #1683 from lambday/develop

reduced size and accuracy for speeding up unit-tests
set epsilon 1e-4 by default for krr
Merge pull request #1685 from votjakovr/feature/gp_refactoring

Set epsilon=1e-4 by default for krr
added a new ica notebook using image data, fixed typo in other notebooks
added set seed for failing unit-test
Merge pull request #1689 from pickle27/develop

added a new ica notebook using image data, fixed typo in other notebooks
Merge pull request #1690 from lambday/develop

added set seed for failing unit-test