Submodule

This PR needs some discussion before someone decides to merge it.  The PR adds the [conda-recipes-scitools](https://github.com/SciTools/conda-recipes-scitools/) repository as a submodule for ioos/conda-recipes.  The main advantages is to lift the weight of maintaining redundant packages.  Scitools guys (iris developers) are doing a great job with their conda packages and we can take advantage of that.

Some Pro and Cons we have to consider before merging:

- Sometimes it is desirable to diverge from the main releases.  That did happen with issue https://github.com/SciTools/iris/pull/1291
- It adds some extra commands to keep the repository up-to-date:
  * `git submodule init`
  * `git submodule status`
  * `git submodule update`

The main pro is the fact that we get the following packages "for free":
- biggus
- cdat-lite
- ecmwf_grib
- libmo_unpack
- proj4
- pyke
- python-dateutil
- cartopy
- cfchecker
- jasper
- owslib
- pyepsg
- pyshp
- udunits