tox: add config file

By using tox, you don't have to worry about maintaining a virtual
environment yourself with sphinx and the zerovm-sphinx-theme.
index: shorten title

The long title took up a lot of space in links on other pages.
index: split off subprojects into their own section
index: create a Zebra section

I plan to put a section about getting started before this.
contributing: add stub document about contributing
release-schedule: added stub document
contact: stub document about getting in contact
Merge pull request #7 from mgeisler/dev-process

Stub documents and proposals about our development process
contact.rst: fix spelling errors
contributing.rst: reword coding style description
Merge pull request #8 from larsbutler/typos-and-wording

Typo fixes and rephrasing
restructuing documentation
more restructuring of docs
split zebra documentation into multiple smaller pages
replaced TODOs with short but complete descriptions
Merge pull request #9 from byeager/master

replaced TODOs with short but complete descriptions
glossary.rst: Initial commit

Contains definitions of terms commonly used in the ZeroVM ecosystem.
index.rst: reword the heading of the main TOC

I want to add a `Glossary` to the TOC, and so changing "Getting
Involved" to a more general "Getting Started with ZeroVM" for other
types of general information.

For example, in the future I also want to add tutorials, installation
guides, etc., and such topic make more sense under the new heading.
index.rst: add glossary to main TOC
index.rst: remove trailing whitespace