Luer lock

**update Dec 14, 2015
Luer lock is now printable... but can still be improved. The opening ends up being very small, so a small drill or a hot needle passed through it might be a good idea. Doesn't seem to fully lock either... needle continues to spin when I turn it
...The hole is now bigger, but it doesn't seem to be liquid tight when I print it.. and it still continues to spin when I turn a needle in it.

A luer-lock to be added to models that deal with fluids.

The scaling hasn't been optimized for FFF printers (tolerances are too tight)... The centre needs to be scaled down, and the outside ring needs to be scaled up.

It would probably be good to print with a higher resolution printer, like an SLA one though.