Add google analytics to docs
Merge pull request #426 from aterrel/google-analytics

Add google analytics to docs
expr: selection doesn't fail on non-rowwise child

Effect is that nested selections or really any selection of a non-rowwise
is still acceptable.

Thanks @talumbau for reporting
expr: rowwise docstring
Merge pull request #445 from mrocklin/selection-path-check

expr: selection doesn't fail on non-rowwise child
minor edits to docs reflecting recent changes
doc: index header looks more like README
doc: start api documentation
doc: docstrings adhere to numpydoc
add numpydoc to conf.py
improve table docstring
doc: rearrange api
header links are all internal
simplify front page
doc: add people