Merge pull request #1718 from van51/develop

Fixed notebook error upon conversion
workaround ipython crash for this notebook
FGM notebook update: using subset of training data
Merge pull request #1719 from hushell/develop

FGM notebook update: using subset of training data
ensure that binary labels are in -1/+1 - but if they don't contain +1 or
-1 just warn the user instead of throwing exceptions (Fixes #1711)
fix a nubmer of warnings
changed .travis.yml