tf_helpers: - generalized Logger to be more versatile. - bug fixes in VersionAwareSaver - added `get_variable_histogram` to just get histo variable - added ImageSaver
tf_helpers:
- generalized Logger to be more versatile.
- bug fixes in VersionAwareSaver
- added `get_variable_histogram` to just get histo variable
- added ImageSaver

fab-jul/fjcommon