bug fix: removed \r in textversion's content because of a comment position bug in pre_edit. Added a save function to TextVersionManager to do so. Also removed cleaning \r before computing diffs because it should not be necessary anymore.

def update(obj, kwargs):
    """
    Update obj attributes with values from kwargs
    """
    for k,v in kwargs.items():
        if hasattr(obj,k):
            setattr(obj,k,v)