Remove unused code and on-screen palette

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Remove debug code

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Add near clipping test to visu

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Fix visu window coordinates

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Fix visu object face clipping

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>