Simplify range
Reduce optimizations via boiler + logic
don't use empty initialiser `for` pattern

https://github.com/jashkenas/underscore/pull/1710#issuecomment-47545879

The one exception is `_.indexOf` where that pattern is needed.
Merge pull request #1714 from megawac/range

Simplify range
Optimization of _.reduceRight
reduceRight: More elegant check for no intial val
reduce*: one length collection test coverage
Merge remote-tracking branch 'megawac/reduce'
Merge pull request #1669 from megawac/reduceRight

More elegant _.reduce*