Add development documentation

Some developers would like to use IDEs, such as Eclipse or IDEA, for
developing Stirling. Describe how to do it so that there is no need
to add references and dependencies to the IDEs into Stirling.

Signed-off-by: Jussi Virtanen <jussi.k.virtanen@gmail.com>
Merge pull request #160 from jvirtanen/features/development-documentation

Add development documentation