Merge pull request #5 from mlubin/master

update BinDeps usage
Small build.jl fix
Merge branch 'master' of https://github.com/loladiro/GraphViz.jl

Conflicts:
	deps/build.jl
Small cleanup and remove aginit

aginit isn't needed for cgraph it's only a thing for libgraph which is
deprecated and not used.
When not precompiling make sure the environment variable gets set as early as possible.
Fix #6
Yet another good use for the `preload` hook.
Merge pull request #10 from staticfloat/master

Yet another good use for the `preload` hook.