Added more utilities in JsonUtils/Joltutils

      moved methods not from JsonUtil interface to JoltUtils
      added methods: navigateSafe, isEmptyJson, listKeyChains, toSimpleTraversrPath, added tests
      Marked older methods as depricated

Change-Id: I34e6b940f1d96580d5685edca3c8603aa388fad8
Merge pull request #99 from bivasdas/jsonUtil

Added more utilities in JsonUtils