Test declarations

[BosqueLanguage]

We need to cleanup the test declaration. We need to resolve a bit about how developers can define classic unit-tests, inline example tests, and fuzzing/property based tests.

• Maybe let them be inline in other Bosque code? Annotations to control category and Grouping?
• Then we can also do special treatment for dedicated test files.
• Integrate nicely with examples feature.

This needs a little design thought + some work in the front-end to gather and manage anything extracted as test related. Also we will want to build a separate test-runner utility that parallels the compiler in terms of taking a set of files, extracting all of the specified tests, building the assembly, then nicely running the tests. Ideally we would like to have failing test debugging integrated from the beginning as well -- e.g. if we have a failure setup a repro that is ready to lanuch and debug.

[BosqueLanguage]

Language and Parser/Checker support for examples landed in #86

Also added a spec option to flag for inclusion as examples in doc-gen (and test that the examples actually work)!