RFR: Add toString to JEPBot

[Erik Joelsson]

Add a toString() method to JEPBot in line with other bots. This helps a lot when searching bot logs.

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Commit messages:
 - Add toString to JEPBot

Changes: https://git.openjdk.java.net/skara/pull/1322/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1322&range=00
  Stats: 5 lines in 1 file changed: 5 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/skara/pull/1322.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1322/head:pull/1322

PR: https://git.openjdk.java.net/skara/pull/1322