Relax Wayland version checks.

Instead of insisting Wayland to be at a specific version (1.4.0 at this
time of writing), make it a ">=" check.

This is necessary for Tizen, which has recently moved to Wayland 1.5.0,
and it also makes the lives of most developers easier as they can use a
version closer to the bleeding edge as well.

Since we now support Wayland versions newer than 1.4.x, a note has been
added to the README to mention XDG Shell support only works with the 1.4
series.
Merge pull request #247 from rakuco/relax-wayland-version-check

Relax Wayland version checks.
Update xdg-shell for Weston 1.5

The protocol has heavily changed, update it so it builds and works
with the newest Weston 1.5 release.

Add some README instructions.

XWALK-1382

Signed-off-by: Manuel Bachmann <manuel.bachmann@open.eurogiciel.org>
Update README instructions for xdg_shell.
Update README.md

Fix the minimum supported Wayland version.
Update README.md

Fix typo.
Temporarily remove ozone dependency for gl

The old implementation will result that the third party window system can't depend on ui/gl
because of cycling dependency. So temporarily remove ozone dependency for gl.

BUG=240
Merge pull request #246 from qjia7/master

Fixed the compile error
Merge pull request #249 from qjia7/patch

Temporarily remove ozone dependency for gl
Add myself to the AUTHORS file