Use __all__ in __init__.py

Address #52

Use __all__ in __init__.py for sake of API documentation. Also added
`-dev` to the version number.
Add files to build docs.
Remove workshop names from notebooks

Address issue #52

Remove spaces and numbering in names of notebooks. Remove superfluous
notebooks.
Fix broken Makefile

Address issue #52

Makefile was not iterating over dependencies for each target. Now
using % to expand names in list of targets and dependencies.

 * Add Sphinx output directories to .gitignore.

 * Add all notebooks to docs.

 * Remove defunct elasticity notebook.
Merge branch 'issue52-docs'

Address issue #52