Merge code refactoring changes back into default branch.  Code moved out of esmond.api.api.py -> constants into __init__.py, auth and throttling code into auth.py and data handling code into dataseries.py.
update architecture diagram
fix formatting and add diagram to architecture section
fix formatting and refs in intro
documentation updates
use esnet docs theme in Sphinx
Squashed 'docs/_esnet/' content from commit c02bf57

git-subtree-dir: docs/_esnet
git-subtree-split: c02bf57d43dbfcd7c727cdd17c54f0a480279f9a
Merge commit 'f70fd5bc614e61f47bc46dda40f8b42e4fd55e98' as 'docs/_esnet'
add favicon and link to github page
translate .hgignore to .gitignore; add symlink in docs/_static
Merge branch 'develop' into mmg-gap