Add the ability to include other test files

[jszwedko]

Adds an include directive that operates similar to load but allows you to include other bats test files rather than just bash scripts which allows for a simple way to DRY up similar tests.

See the added tests for a simple example of how this functionality might be used.

I can add documentation for this, but wanted to get feedback on the implementation first.

Thank you!

[jszwedko]

Addresses #99

[jszwedko]

Any feedback @sstephenson ?

[rjernst]

Any update here? This has sat around for 6 months, and is really useful...

[sstephenson]

Any update here? This has sat around for 6 months, and is really useful...

I’m aware there are lots of issues that need attention, but Bats is a personal project and I don’t have any time for it right now. I am looking for a full-time maintainer. Maybe that’s you?

[nkakouros]

I just found this PR. I have a similar PR here