Criterion/report.tpl : Mention ghc-7.8.3 and and add New4.
Fix benchmarking.

* Delete old bench-integer.hs.
* Rename old new-bench-integer.hs to bench-integer.hs.
* Ditch bogus benchmarks with really spikey KDE graphs.
* Implement new benchmarks for addition/subutraction of small and big
  Integer values.