Added any missing license headers to all files

TShockAPI/DB/UserManager.cs

@@ -1,4 +1,4 @@
-/*   
+/*
 TShock, a server mod for Terraria
 Copyright (C) 2011 The TShock Team
 
@@ -15,7 +15,6 @@ GNU General Public License for more details.
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
-
 using System;
 using System.Data;
 using System.IO;