[svn] Minor fixes and cosmetic changes.

[svn] Minor fixes and cosmetic changes.

(uri_merge): Get rid of uri_merge_1.
(uri_merge): Merge "foo//", "bar" as "foo//bar", not "foo///bar",
i.e. don't add an extra slash merely because BASE ends with two
slashes.
(parse_credentials): Renamed from parse_uname.  Rewrittern in
standard [beg, end) calling style.
(url_skip_credentials): Renamed from url_skip_uname.  Made static.
(url_skip_credentials): Include # and ; as terminators.  Old code
would mistakenly consider "http://foo.com#hniksic@iskon.hr" to
contain a username.
(url_skip_scheme): Removed because it was unused.
(url_has_scheme): Require "scheme" to be at least one char long.