Implementation, closes #128
Merge pull request #129 from BlueMountainCapital/GH128

Implementation of #128 on mainline
Added tryLookupObservation to SeriesModule for symmetry, per #128
Merge branch 'GH128' into mainline

* GH128:
  Added tryLookupObservation to SeriesModule for symmetry, per #128
Merge changes
Add pivot table docs, minor stylistic code changes

The pivot table function is cool :-) I added a few samples to the docs.
I also did a few minor changes (as I was reading the code) - there
was absolutely nothing wrong with it - I did just a few minor stylistic
tweaks and adjusted it to a small notebook screen!