Add pp to per.

Need more testing (i.e. with syntax).

Signed-off-by: Jerome Maloberti <jmaloberti@gmail.com>
Better defaults for Installable and Buildable.

Signed-off-by: Jerome Maloberti <jmaloberti@gmail.com>
Revert a bad commit: -safe-string flag prevents the test to run with ocaml < 4.02.

Signed-off-by: Jerome Maloberti <jmaloberti@gmail.com>