Spelling error from previous PR (sorry).
Added reference to Greg Hewgill's version checker tool.
Added section on continuous integration (Travis-CI and Appveyor and links)
Marked off todo items.
Merge pull request #79 from cjrh/spelling-error

Spelling error from previous PR (sorry).
Merge pull request #81 from cjrh/greghewgillref

Added reference to Greg Hewgill's version checker tool.
Merge pull request #82 from cjrh/continuousintegration

Added text regarding continuous integration