The `.` character in the auth part of the SIP URI is mishandled

[jbg]

Because of https://github.com/Televiska/rsip/blob/master/src/common/uri/auth.rs#L103 it's not currently possible to parse a Uri that contains a . before the @. The Uri can be constructed manually, but not being able to parse makes handling redirection tricky.

[jbg]

#49 fixes this