BUrl: use a regex to parse URLs

* The RFC provide a regular expression for URI parsing, so just use it.
 * Allows parsing URIs with missing components (no scheme or authority)
 * This allows to parse relative URLs as expected
 * Can also handle things such as data: or mailto:
 * Also more fixes to handling of incomplete URIs, some flags weren't
always set to the right values.

This gets Windows Live Mail (or is it called Outlook?) working, with
some other fixes on WebKit side.

headers/os/net/Url.h

@@ -16,6 +16,7 @@ public:
 								BUrl(const char* url);
 								BUrl(BMessage* archive);
 								BUrl(const BUrl& other);
+								BUrl(const BUrl& base, const BString& relative);
 								BUrl();
 	virtual						~BUrl();
 
@@ -24,12 +25,12 @@ public:
 			BUrl&				SetProtocol(const BString& scheme);
 			BUrl&				SetUserName(const BString& user);
 			BUrl&				SetPassword(const BString& password);
+			void				SetAuthority(const BString& authority);
 			BUrl&				SetHost(const BString& host);
 			BUrl&				SetPort(int port);
 			BUrl&				SetPath(const BString& path);
 			BUrl&				SetRequest(const BString& request);
 			BUrl&				SetFragment(const BString& fragment);
-			void				Redirect(const BString& newLocation);
 			
 	// URL fields access
 			const BString&		UrlString() const;
@@ -88,7 +89,6 @@ public:
 private:
 			void				_ResetFields();
 			void				_ExplodeUrlString(const BString& urlString);
-			void				_ExplodeAuthority();
 
 	static	BString				_DoUrlEncodeChunk(const BString& chunk, 
 									bool strict, bool directory = false);