RFR: 8249821: Separate libharfbuzz from libfontmanager

[Philip Race]

Bug: https://bugs.openjdk.java.net/browse/JDK-8249821
Webrev: http://cr.openjdk.java.net/~prr/8249821/

This fix breaks out libharfbuzz from libfontmanager.
As well as building I've done extensive testing on all platforms.

I have tweaked the disabled warnings so we don't have un-needed duplication
but it is not a goal of this fix to resolve them.
There's a bug (JDK-8074844) already filed to resolve them for 
fontmanager and
that should be easier to fix now.

-phil.