adding ability to interpolate Index and Index Type names from Field values
Fixing split logic and adding extra message attributes to interpolateFlag
updating CHANGES.txt for issue #356
updating docs for issue 356
adding tests in elasticsearch output for interpolatedFlag function
fixing typo in @type test
merging features/issue_356 into dev
Merge pull request #385 from michaelgibson/features/issue_356

Features/issue 356