Adding tests for multi-label flag and label-separator is used in predictions
Adding test for models retrieved by tag and bug fixing for this option
Adding doc for the --model-tag retrieval of multi-labelled models
Adding test files and changing a bit multi-label docs examples
Changes label for loop now that labels are previously sorted
Some bug fixing and pep8, pylint improvements
Changes suggested in docs, new --no-multi-label flag and test for labels
Some more comment improvemnts