Add code coverage reporting to the library. Expanding coverage to come later

[dfellis]

cc @Raynos

The coverage on the childProcess code is wrong since istanbul cannot check coverage in child processes, yet.

Also, wouldn't mind if you put up some PRs to make the module structure a bit more "standard", though I'll prefer to keep npm run realpublish until you've thought over another way to auto-generate code documentation. :)

[coveralls]

Changes Unknown when pulling 48760e1b83d8bbc7c3ab63090b01d05235980757 on code-coverage into \ on master**.

[coveralls]

Changes Unknown when pulling 52f00fa5d18f2fcc106c43ace28fd385e4509d51 on code-coverage into \ on master**.

[coveralls]

Changes Unknown when pulling 52f00fa5d18f2fcc106c43ace28fd385e4509d51 on code-coverage into \ on master**.

[Raynos]

lgtm.

@dfellis I do this this ( https://github.com/uber/uncaught-exception/blob/master/test/shutdown.js#L22-L44 ) to code coverage child processes.

[dfellis]

@Raynos holy crap that looks painful. Any way you can make that pattern a module and/or get it merged into istanbul? :)

[Raynos]

@dfellis i can make it a module at some point

[Raynos]

if i make a module i want to support, spawn, exec & cluster.fork