'Construct a FeatureProfile object from a base64 signature.
>>> FeatureProfile.from_signature(\'=////////Hw==.53.9\')
FeatureProfile([(\'apps\', True), (\'packaged_apps\', True), ...)'

@classmethod
def from_base64_signature(cls, signature):

    (string, limit, version) = signature.split('.')
    limit = int(limit)
    bitfield = FeaturesBitField.from_base64(string[1:], limit)
    return cls.from_list(bitfield.to_list(), limit=limit)
