New README and license

targets/efm32/src/printing.c

@@ -1,3 +1,24 @@
+/*
+ * Copyright (C) 2018 SoloKeys, Inc. <https://solokeys.com/>
+ * 
+ * This file is part of Solo.
+ * 
+ * Solo is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * Solo is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with Solo.  If not, see <https://www.gnu.org/licenses/>
+ * 
+ * This code is available under licenses for commercial use.
+ * Please contact SoloKeys for more information.
+ */
 #include "em_chip.h"
 #include "em_cmu.h"
 #include "em_emu.h"