Core Keyremap Allow setting keymap from plugin

Allow setting and removing keyremap on the fly

It was pretty annoying trying to work out a keyremap with a restart
required to set the remap and was quite annoying when I was no
longer able to navigate to the plugin or filebrowser due to setting
the wrong remap

now you can try out a keymap and if it doesn't work a restart will
sort things out

Change-Id: I848fb3bd759f9684ac2497324a371f92b7464f7b

apps/core_keymap.h

@@ -24,12 +24,16 @@
 #include <stdbool.h>
 #include <inttypes.h>
 #include "config.h"
+#include "action.h"
 #define KEYREMAP_VERSION 1
 #define KEYREMAP_HEADERID (LAST_ACTION_PLACEHOLDER | (TARGET_ID << 8))
 
 /* If exists remap file will be loaded at startup */
 #define CORE_KEYREMAP_FILE ROCKBOX_DIR "/keyremap.kmf"
 
+/* Allocates core buffer, copies keymap to allow buttons for actions to be remapped*/
+int core_set_keyremap(struct button_mapping* core_keymap, int count);
+
 /* open_key_remap(filename , *fd (you must close file_descriptor), *fsize)
  * checks/strips header and returns remaining count
  * fd is opened and set to first record