Improvements of "gf -server" mode and related setup

"gf -server" mode now contains everything needed to run the minibar and
the grammar editor (including example-based grammar writing).

The Setup.hs script installs the required files where gf -server can find them.
These files have been moved to a new directory: src/www.

The separate server program pgf-http is now obsolete.

src/www/gfse/localstorage.js

@@ -0,0 +1,21 @@
+
+// We use localStorage to store the grammars,
+// see http://diveintohtml5.org/storage.html
+
+var local={
+    prefix:"gf.editor.simple.grammar",
+    get: function (name,def) {
+	var id=this.prefix+name
+	return localStorage[id] ? JSON.parse(localStorage[id]) : def;
+    },
+    put: function (name,value) {
+	var id=this.prefix+name;
+	localStorage[id]=JSON.stringify(value);
+    },
+    remove: function(name) {
+	var id=this.prefix+name;
+	localStorage.removeItem(id);
+    },
+    get count() { return this.get("count",0); },
+    set count(v) { this.put("count",v); }
+}