Implement autoupdate/automigrate

The implementation forks a new node process to execute the method in the context of the target project.

Close #106.

/to @ritch please review
/cc @seanbrookes @altsang 

@rmg The tests require a local MySQL database to be configured for the tests - see `bin/setup-mysql`. What is needed to get such setup on CI build slaves? Shall I disable those tests on Jenkins for the time being?
Sure, I am happy to make that change once we decide what env variables work best for our Jenkins CI.

As far as the developer flow is concerned, I find it easier to run `node bin/setup-mysql.js` once, than have to remember what env variables to set for the test.