Log Message:
Updated graphviz to 2.40.1.

December 21, 2016
	- Remove usage of ast_common.h
December 20, 2016
    - Release 2.40.0
        - network-simplex fixes and optimization (Stephen North)
	- built-in tred tool now available in the various swig generated
	language bindings (John Ellson)
	- number rounding added to SVG renderer (same as PS and TK rounding)
	to aid regression testing. (John Ellson)
	- additional regressson test framework, used in Travis CI builds. (Erwin Janssen)
	- PHP7 support (requires swig-3.0.11 or later). (John Ellson)
	- Allow user to specify clustering algorithm in gvmap. (Emden Gansner)
	- Add Sierpinski graph generator to gvgen. (Emden Gansner)
	- Extensive code cleanup (Erwin Janssen)
	- Removal of libgd source - use vanilla libgd from separate install
	- Windows builds (Erwin Janssen)
	- Appveyor CI for automated Windows build testing (Erwin Janssen)
	- Travis CI for Fedora/Centos builds (Erwin Janssen)
	- Added JSON output format, -Tjson  (Emden Gansner)
	- New curved arrowhead, cylinder node shape.
	- Resolves bugs: 2599, 1172
June 18, 2016
	- Experimenting with Travis CI
February 13, 2016
	- Add cylinder shape for databases.
	- Free installed plugins
	- Update makefile for dot so that the using libpanco_C in the static build \ 
include PANGOFT2
        as well as PANGOCAIRO_LIBS (needed for some versions of Ubuntu)
February 1, 2016
	- Add json output format
April 26, 2015
	- output class value in svg files
September 9, 2014
	- Add plain shape for use with HTML-like labels.
August 12, 2014
	- Add icurve arrowhead.
July 28, 2014
	- Revert to old, translate to origin semantics in neato, etc. Add flag \ 
notranslate if that is
          what the user desires.