Call for examples! (Ideas or PRs)

[dtrudg]

This examples repository has become a bit stale, so we need to revise what's here, and add additional content that usefully demonstrates how to build different kinds of Singularity containers.

We welcome contributions of examples as PRs, or ideas filed as replies here, or as new issues.

Ideally we'd have a nice mix of example definition files for applications from a range of different domains.