README: clarify libweston purpose/goals.

v2: Rewrap, add a couple of missing words (Pekka).
v3: Use alternative wording (Yong).

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
1 file changed