Fixed array as initializer (illegal pre-C++11)

src/Module.h

@@ -149,7 +149,7 @@ class Module {
     /*!
       \brief Line feed to be used when sending AT commands. Defaults to CR+LF.
     */
-    char AtLineFeed[3] = "\r\n";
+    char AtLineFeed[3] = {'\r', '\n'};
 
     /*!
       \brief Basic SPI read command. Defaults to 0x00.