RFR: JDK-8290011: IGV: Remove dead code and cleanup [v7]

[Tobias Holenstein]

> Remove dead code from the IGV code base. There are many unused or redundant functions in the code

Tobias Holenstein has updated the pull request incrementally with three additional commits since the last revision:

 - delete unused Graph.java and Edge.java
 - Code style update
 - remove unused MouseOverAction

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/10197/files
  - new: https://git.openjdk.org/jdk/pull/10197/files/35f681c8..419db83c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10197&range=06
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10197&range=05-06

  Stats: 1076 lines in 17 files changed: 163 ins; 790 del; 123 mod
  Patch: https://git.openjdk.org/jdk/pull/10197.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10197/head:pull/10197

PR: https://git.openjdk.org/jdk/pull/10197