http://cr.openjdk.java.net/~mchung/jdk9/webrevs/8173374/webrev.00/
This is the first step to enable generating dot graph to be included in module summary javadoc, if desired. jdeps already supports generating the dot graph for modules. This patch converts GenGraphs build tool to use jdeps implementation as well as fixes jdeps to work with -apionly to generate a dot graph containing `requires transitive` edges only. Mandy [1] https://bugs.openjdk.java.net/browse/JDK-8173303
