add support for po files without headers

basically fix all the examples.

lib/po.js

@@ -64,11 +64,16 @@ PO.parse = function (data) {
     data = data.replace(/\r\n/g, '\n');
     var po = new PO();
     var sections = data.split(/\n\n/);
-    var headers = [sections.shift()];
+    var headers = [];
     //everything until the first 'msgid ""' is considered header
-    while (headers[headers.length - 1].indexOf('msgid ""') < 0) {
+    while (sections[0] && (headers.length === 0 || headers[headers.length - 1].indexOf('msgid ""') < 0)) {
+        if (sections[0].match(/msgid "[^"]/)) {
+            //found first real string, adding a dummy header item
+            headers.push('msgid ""');
+        } else {
             headers.push(sections.shift());
         }
+    }
     headers = headers.join('\n');
     var lines = sections.join('\n').split(/\n/);