jquery-keyboard: new package

Add the jquery-keyboard package based on Simon Dawson's patch with a
newer version and improvements (license, select jquery, install
layouts).

[Peter: don't use install -D when destination is a directory]
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>