RFR: JDK-8178042 Allow custom taglets

[Mandy Chung]

> On Apr 19, 2017, at 4:57 AM, Magnus Ihse Bursie <magnus.ihse.bursie at oracle.com> wrote:
> 
> Please review this simple change to allow custom to add specialized javadoc taglets.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8178042
> WebRev: http://cr.openjdk.java.net/~ihse/JDK-8178042-allow-custom-taglets/webrev.01

Looks fine to me.

Mandy