Simplify \ct and make it work on more cases

Signed-off-by: Damien Cassou <damien.cassou@gmail.com>
Immediately exit when pdflatex can't work

Signed-off-by: Damien Cassou <damien.cassou@gmail.com>
Add the logo otherwise the sample won't compile

Signed-off-by: Damien Cassou <damien.cassou@gmail.com>
Don't add too many samples

Signed-off-by: Damien Cassou <damien.cassou@gmail.com>