svnwrap: fix handling of quotable URLs (fixes #197, refs #132) The way hgsubversion handles URLs that may or may not be quoted is somewhat fragile. As part of fixing issue 132 in 925ff8c5989c, the path component of URLs was always quoted. The URL has been attempted encoded since the initial check-in. The fix from 925ff8c5989c was incomplete; reverting it allows us to clone a URL with a '~' in it.[1] Encoding the URL as UTF-8 seldom works as expected, as the default string encoding is ASCII, causing Python to be unable to decode any URL containing an 8-bit character. The core problem here is that we don't know whether the URL specified by the user is quoted or not. Rather than trying to deal with this ourselves, we pass the problem on to Subversion. Then, we obtain the URL from the RA instance, where it is always quoted. (It's worth noting that the editor interface, on the other hand, always deals with unquoted paths...) Thus, the following invariants should apply to SubversionRepo attributes: - svn_url and root will always be quoted. - subdir will always be unquoted. Tests are added that verify that it won't affect the conversion whether a URL is specified in quoted or unquoted form. Furthermore, a test fixture for this is added *twice*, so that we can thoroughly test both quoted and unquoted URLs. I'm not adding a test dedicated to tildes in URLs; it doesn't seem necessary. [1] Such as <https://svn.kenai.com/svn/winsw~subversion>.