Added documentation, removed library from Makefile

Making the mqtt as a .a library is a project for a later date.
The recipe was broken and so was removed to avoid confusion.

Added the Mozilla License header to the new files. Also a few
small corrections and additions to the Doxygen documentation.

Signed-off-by: A.M. Rowsell <amrowsell@frozenelectronics.ca>

onewire.c

@@ -1,3 +1,7 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
 #include <stdint.h>
 #include "os_type.h"
 #include "osapi.h"
@@ -5,7 +9,7 @@
 #include "gpio.h"
 #include "onewire.h"
 
-#define OWBUS BIT5
+#define OWBUS BIT5 /**< This define determines which pin is used */
 
 sint8 ICACHE_FLASH_ATTR reset(void) {
   uint32_t time;