Make umbrello xmi id's XMI standard conform.

Add prefix 'u' to generated xmi id's and convert spaces in id's
into '_' for root folder names.

umbrello/umldoc.cpp

@@ -149,7 +149,9 @@ void UMLDoc::init()
     };
     for (int i = 0; i < Uml::ModelType::N_MODELTYPES; ++i) {
         const QString rootName = QString::fromLatin1(nativeRootName[i]);
-        m_root[i] = new UMLFolder(rootName, Uml::ID::fromString(rootName));
+        QString id = rootName;
+        id.replace(QLatin1Char(' '), QLatin1Char('_'));
+        m_root[i] = new UMLFolder(rootName, Uml::ID::fromString(id));
         m_root[i]->setLocalName(localizedRootName[i]);
     }
     createDatatypeFolder();

umbrello/uniqueid.cpp

@@ -25,7 +25,7 @@ Uml::ID::Type m_uniqueID;
  */
 Uml::ID::Type gen()
 {
-    m_uniqueID = std::string(KRandom::randomString(12).toLatin1());
+    m_uniqueID = std::string('u' + KRandom::randomString(12).toLatin1());
     return m_uniqueID;
 }