Fix: missing commas in struct constructors
Fix: missing commas in struct constructors

The way we used to print comma separated lists in `OpenCLPrinter`
led to invalid code in some situations (namely when one of the elements
of the list was equal to the last one).

Add a generic `printList` method which prevent this to happen.

lift-project/lift,lift-project/lift,lift-project/lift,lift-project/lift,lift-project/lift