tablet: Correct grammar and punctuation

Correcting minor grammar and punctuation affords clarity.
Standardize the use of 'surface local coordinates' in lieu of 'surface relative'.
Capitalize Wayland where appropriate, similar to other occurences.

Signed-off-by: Yong Bakos <ybakos@humanoriented.com>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>