Initial setup
First working version with minimal Graph API and ImplicitGraph as test class.
Merge branch 'master' of https://github.com/monora/jgraph
Merge branch 'master' of https://github.com/monora/jgraph
Removed retrolambda support

This caused this error:

[ERROR] src/java/jgraph/src/test/java/org/jgraph/ImplicitGraphTest.java:[17,17] cannot access org.jgraph.Graph
  bad class file: /src/java/jgraph/target/classes/org/jgraph/Graph.class
    default method found in version 51.0 classfile
    Please remove or make sure it appears in the correct subdirectory of the classpath.
[INFO] 1 error