Add thumbnail for cinnamon theme specs
Add metacity thumb for cinnamon specs
Merge pull request #158 from RavetcoFX/a2

Add metacity thumbnail for cinnamon specs
Merge pull request #157 from RavetcoFX/a1

Add gtk3 thumbnail for cinnamon theme specs
change to light color

Signed-off-by: xiehuc <xiehuc@gmail.com>