Add meson build system

This patch adds a complete meson build system, including tests and
install. It has the necessary hooks to allow it be used as a subproject
for other meson based builds such as mesa.

Signed-off-by: Dylan Baker <dylan.c.baker@intel.com>
Reviewed-and-tested-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>