Rockbox

This patch depends on FS#7704.
It voice enables the chessbox plugin.
Both the game play and the PGN viewer mode can be used eye-free with this patch.
The viewer could use some more care, I'll provide updates as my local version changes.
This patch is probably not fit for inclusion yet, we'd need to figure out a way to provide plugin specific lang/voice files first.
It is being posted here because it has prooven very useful to me and some friends in the past, and can be used as-is on targets that are not that tight on memory and can rebuild their own .voice files.

 lang/english.lang               |  322 ++++++++++++++++++++++++++++++++++++++++
 plugins/chessbox/chessbox.c     |   99 +++++++++++-
 plugins/chessbox/chessbox_pgn.c |   13 +
 3 files changed, 424 insertions(+), 10 deletions(-)