Fix #4: URL type should not allow params

### Don’t merge this yet! (again)

Okay, I started over from scratch.  But THIS time I tracked down the error!

## The Error is…

For some reason, the error occurs when the testing gets to `http://aspaass.no/kontakt/Aspaas%20Sykler.vcf`.  

It’s choking  on the `Å` character, even though it shouldn’t.

If you goto the `test_package.py` and comment out `'http://aspaass.no/kontakt/Aspaas%20Sykler.vcf'` ([line 192](https://github.com/Zearin/vcard/blob/bugs/4_no_params_for_url_type/vcard/test/test_package.py#L192)), the tests pass. 

### But here’s the weird part…

In `vcard_validators.py`, if you goto the block that validates the `URL` type ([line 982](https://github.com/l0b0/vcard/pull/28/files#diff-2b847fe9cbf31412a790dd359abafe82R982)) and comment out the whole thing, *the error goes away*!

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This makes *no* sense to me.  Why would URL validation confuse the tests that happily opened the same file before?

Can you help me figure this out, @l0b0 ?