Make cursor hollow on blur

Fix #79

demo/style.css

@@ -21,6 +21,6 @@ h1 {
     padding: 2px;
 }
 
-#terminal-container .terminal .terminal-cursor {
+#terminal-container .terminal:focus .terminal-cursor {
     background-color: #fafafa;
 }

src/xterm.css

@@ -51,6 +51,12 @@
     color: #000;
 }
 
+.terminal:not(:focus) .terminal-cursor {
+    outline: 1px solid #fff;
+    outline-offset: -1px;
+    background-color: transparent;
+}
+
 /*
  *  Determine default colors for xterm.js
  */