Log Message:
Update to 1.19

gama now requires c++11.  It's likely that 1.18 did also, but that
this was less obvious.

Besides items noted in upstream NEWS, two pkgsrc patches were applied
upstream.

Version 1.19 June 2017

* fixed a bug introduced in 1.16, reported by Pierre Bosser
	<pierre.bosser@ensta-bretagne.fr>. Implicit value of
	covariance band in XML adjustment output is -1 (full
	bandwidth).