[CONTRIB] Make it easier to work on libdefs

Everytime I tried to write libdefs, I usually took one of my projects which are already using other flow-sources and then work in this project folder… which is not always ideal, since sometimes you want to use a more current version of flow, or you depend on other libdefs which will break then…

So I can think of these simple solutions:

• Either add the eslint / flowtype tooling to the root of this project, so whenever I work in definitions, my tooling works
• Create a cli command which turns an empty directory to a testing facility (similar to how my javascript-fatigue project works… it creates me all the scruff I need to get down to work for a redux-project)
• Create a pre-configured playground directory inside flow-typed, which is set up with its own package.json, similar to the cli directory

[ryyppy]

Just to sum up this whole discussion:

We want to be able to test specific libdefs with specific tests more easily and independent from existing projects.

We need a command similar to this:

$ flow-typed run-tests --libdef=./redux-saga_1.0.x.js --testFile=./test_redux-saga_1.0.x.js --flowVersion=v0.27.0 --watch

Whenever I change my libdef / test-file, it should re-run the tests (similar to how mocha etc. would do it) Got this on my radar.

[ryyppy]

@ctrlplusb I agree, IMO this is something which is absolutely required for a 1.0 release… AFAIK @thejameskyle is working on a flow handbook (https://twitter.com/thejameskyle/status/751889868288978944) … maybe this would be a good opportunity to piggy-back?