Implement NameResolver application

[clbarnes]

Catmaid client application which allows users to put in the string name/ title of an object and get back its database ID. Currently has implementations for users and stacks, but it's trivial to add more as they become useful.

Resolves #21.

PR is a bit noisy because I did some significant refactors (as the stable of CatmaidClientApplications is growing) and I blackened the files I touched.

The important changes are

• catpy/applications/nameresolver.py
  • implementation (caches HTTP responses, ensures unique matches)
• tests/test_nameresolver.py
  • tests
• catpy/exceptions
  • collects exception classes for convenience

[aschampion]

Since there's a lot of formatting changes around single-vs-double quotes and newlines, is there a style file that should be in the repo?

e: I suppose this is the point of #29

[clbarnes]

Those are all added by black, or are added for consistency with it (prefer double outer quotes and single inner quotes in e.g. the setup.py requirements), which I intend to enforce at some point (#29 ). But that can come in its own feature branch.

When I do that, I'll add an entry to the CONTRIBUTING file.