Added StringTools

  added required fn.s and updated jolt-core to use them
  subsequently removed apache-commons dependency
  only for jolt-core scr, test still has dependencies
  added tests, asserting against apache commons stringUtils
  Fixes #74

Change-Id: If74a974a6eb2c8351cdc34c8324943fa21bbf1fc
Merge pull request #93 from bivasdas/stringUtils

Added stringUtils