Add instructions for pom-scijava inclusion

Added step-by-step instructions to the pom-scijava README.md detailing
how to incorporate a project into pom-scijava.

This includes having properties for your project, having its version
bumped by the bump-pom-scijava.sh script, and automatic pom-scijava
version bumping in the Bump-POM-SciJava jenkins job.

Completion of these steps for a project should result in total
pom-scijava integration.
Merge pull request #15 from scijava/bump-instructions

Add instructions for setting up a pom-scijava project