Fix documentation bug in reduceSeries function

- The example given uses the wrong order of parameters in the
  documentation. #745
(#745) Add more clear docs for map/reduce

- Add crosslinks and notes about usage
- Note the short forms of the functions
- Expand example for reduceSeries
Add Vagrantfile

- Vagrantfile installs all required and optional dependencies in a
  consistent linux environment for local development and testing.
Merge pull request #1016 from justenwalker/vagrantfile

Add Vagrantfile
Merge pull request #1015 from justenwalker/745-reduceSeries-doc

Fix documentation bug in reduceSeries function