[Fuze+][Keymaps] keymaps for radio and recorder update

1) Now that recording is working a few keymaps update are required.
2) also implement the radio.c file so that fm dedicated keymaps
works.
3) implement some missing fm keymaps
4) manual updated accordingly

Change-Id: I40be3e245853ccb9ed7a5bc5a76fe4ed90772272
Reviewed-on: http://gerrit.rockbox.org/513
Reviewed-by: Amaury Pouly <amaury.pouly@gmail.com>
4 files changed