move xterm lib to assets/external

assets/README.md

@@ -1,7 +1,6 @@
 This directory contains xterm.js 4.16
 
-To update this to a newer version of xterm.js, run 
+To update the xterm library to a newer version of xterm.js, run 
-`npm install xterm.js` in a different directory, 
+`npm install xterm.js` in a different directory, and then copy 
-and copy xterm.js and xterm.js.map and xterm.css here. 
+xterm.js and xterm.js.map and xterm.css and the files for three 
-
+of xterm.js's addons to the external directory. 
-Do the same to three of xterm.js's addons. 

main.go

@@ -224,8 +224,12 @@ func fileHandler(c *gin.Context, fname string) {
 	} else {
 		//c.HTML interprets the file as HTML file
 		//we do not need that for regular files
+		if strings.HasPrefix(fname, "xterm") {
+			c.File(fmt.Sprint("./assets/external/", fname))
+		} else {
 			c.File(fmt.Sprint("./assets/", fname))
 		}
+	}
 }
 
 func main() {