Linux: Add support for SPIDEV (#734)

RPi and Linux refactor.

Add GPIO Sysfs for GPIO operations.

Update configure script.

Fix some cppcheck warnings.

Add serial emulation that prints to stdout.

Fix some file headers.

MyConfig.h

@@ -903,12 +903,12 @@
 #endif
 
 /**
- * @def MY_IS_SERIAL_PTY
+ * @def MY_LINUX_IS_SERIAL_PTY
  * @brief Set serial as a pseudo terminal.
  *
  * Enable this if you need to connect to a controller running on the same device.
  */
-//#define MY_IS_SERIAL_PTY
+//#define MY_LINUX_IS_SERIAL_PTY
 
 /**
  * @def MY_LINUX_SERIAL_PTY
@@ -956,7 +956,7 @@
 #define MY_NODE_LOCK_FEATURE
 #define MY_REPEATER_FEATURE
 #define MY_LINUX_SERIAL_GROUPNAME
-#define MY_IS_SERIAL_PTY
+#define MY_LINUX_IS_SERIAL_PTY
 #define MY_RFM95_ATC_MODE_DISABLED
 #define MY_RFM95_RST_PIN
 #endif