Better support for Quill's "favorite" request

Quill doesn't send a `content` parameter along with the `like-of` data
when performing a "favorite" request.

entry.go

@@ -75,13 +75,23 @@ func parseRequestBody(r *http.Request) (string, error) {
 	return string(bodyBytes), nil
 }
 
+func validEntry(values map[string][]string) bool {
+	if _, ok := values["content"]; ok {
+		return true
+	} else if _, ok := values["like-of"]; ok {
+		return true
+	}
+	return false;
+}
+
 func createEntryFromValueMap(values map[string][]string) (*Entry, error) {
 	if h, ok := values["h"]; ok && (len(h) != 1 || h[0] != "entry") {
 		return nil, errors.New("only entry type is supported so far")
 	}
-	if _, ok := values["content"]; ok {
-		entry := &Entry{
-			content: values["content"][0],
+	if validEntry(values) {
+		entry := &Entry{}
+		if content, ok := values["content"]; ok {
+			entry.content = content[0]
 		}
 		if name, ok := values["name"]; ok {
 			entry.title = name[0]