add randomized unit-tests for IO, increase precision for ASCII writers
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