Merged in derfloh/espurna/def_custom_h (pull request #24)

use an #ifdef to check if we should include the custom.h file

Approved-by: Xose Pérez <xose.perez@gmail.com>

code/espurna/config/all.h

@@ -7,9 +7,14 @@
 
 /*
     If you want to modify the stock configuration but you don't want to touch
-    the repo files you can uncomment the following line and add a "custom.h"
+    the repo files you can either define USE_CUSTOM_H or remove the 
+	"#ifdef USE_CUSTOM_H" & "#endif" lines and add a "custom.h"
     file to this same folder.
     Check https://bitbucket.org/xoseperez/espurna/issues/104/general_customh
     for an example on how to use this file.
+	(Define USE_CUSTOM_H on commandline for platformio:
+	export PLATFORMIO_BUILD_FLAGS="'-DUSE_CUSTOM_H'" )
 */
-//#include "custom.h"
+#ifdef USE_CUSTOM_H
+#include "custom.h"
+#endif