refactor ftface_props example

Signed-off-by: Thomas Hisch <t.hisch@gmail.com>
fix wrong numerical value for ft2font.VERTICAL

Signed-off-by: Thomas Hisch <t.hisch@gmail.com>
use identifiers from ft2font module in ftface props example

Signed-off-by: Thomas Hisch <t.hisch@gmail.com>
Merge pull request #3630 from thisch/ftprop

refactor ftface_props example