flite: new package

[Thomas: rewrap Config.in help text, and use proper format for wchar
comment according to the Buildroot manual.]

Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Cc: Eric Jarrige <eric.jarrige@armadeus.org>
Cc: Julien Boibessot <julien.boibessot@armadeus.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>