Coverage

[qubixes]

• Add minimum 95% testing coverage (currently at 95.03%).
• Improved testing.
• Variable type can now be inferred from the distribution even if the distribution supports multiple variable types.
• MetaVar.get_var_type now returns a TypeError instead of a ValueError for unsupported types.
• A more appropriate error is thrown when a distribution is created with missing parameters.
• The UniqueDistributionMixin now implements __new__ instead of __init__, so that the mixin does not cause the input parameters to change to *args, **kwargs. This should not have any effect on the user, except that the documentation and signature will now give the correct parameters for the unique faker and regex distributions.