Implement XDG compliance, logging, and improved 401 error handling

- Install to ~/.local/bin/winamp-mpris
- Use ~/.local/state/winamp-mpris/bridge.log for logging
- Use $XDG_RUNTIME_DIR/winamp-mpris.pid for PID management
- Add detailed user notification for 401 Unauthorized errors
- Add install.sh for automated, standard-compliant setup
- Include Winamp Web Interface source code and installer in repository

Wawi Source/html.h

@@ -0,0 +1,20 @@
+// html.cpp
+void OpenHTTPHeader(connection * conn, char * type, int length, char * filename);
+void OpenHtmlHeader(connection * conn);
+void Style(connection * conn);
+void RefreshHeader(connection * conn, char * url);
+void CloseHeader(connection * conn);
+void OpenPageBody(connection * conn);
+void OpenHeaderBody(connection * conn);
+void CloseBody(connection * conn);
+void LinkTable(connection * conn);
+void dot(connection * conn);
+void nbsp(connection * conn);
+void Img(connection * conn, int img, char * alt, int dx, int dy);
+void ImgLink(connection * conn, char * link, int img, char * alt, int dx, int dy, int target);
+void Link(connection * conn, char * link, char * text, int target);
+void AboutSource(connection * conn);
+void ImgLinkBar(connection * conn);
+void LinkBar(connection * conn);
+void FullSongInfo(connection * conn);
+void SongInfo(connection * conn);