Improve QML syntax and update license headers.

app/qml/TimeManager.qml

@@ -1,5 +1,5 @@
 /*******************************************************************************
-* Copyright (c) 2013 "Filippo Scognamiglio"
+* Copyright (c) 2013-2021 "Filippo Scognamiglio"
 * https://github.com/Swordfish90/cool-retro-term
 *
 * This file is part of cool-retro-term.
@@ -17,10 +17,9 @@
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *******************************************************************************/
-
 import QtQuick 2.2
 
-Timer{
+Timer {
     default property bool enableTimer: false
     property real time