Tried to merge edits together....
Merge branch 'master' of https://github.com/mdaines/viz.js

Conflicts:
	Makefile
	viz.js
Added ASM_JS=0 option so that builds work with ALLOW_MEMORY_GROWTH
Added necessary changes to allow for layout engine choice.
Fixed issues where viz.c tried to clean up, after the layout engine has already done so.

This causes an error with _free attempting to free memory that has already been freed, and everything fails.
Fixed issue in you the path library was compiled. It was missing some of the sources, which caused failures with some options.
Fixed some functions that were getting stripped out.
Revert graphviz back to v2.28.0
use config.h file and exclude -g for normal builds
revert layout arg; use layout graph attrib instead
camelCased viz (not a class); add fn + pkg exports
mv README.txt to README.md; updated with more docs
make C return a string since stdout works in node
reverted removal of cleanup code

Put in a call to gvFinalize() to mimic the execution of the dot command-line tool
rebuilt viz.js file
Name downloaded sources with version number
Merge branch 'pr/17'
add neato example
it's Viz with a capital V
reinstate .txt readme, add thanks