Add RunInCurrentProcess task and enable in CollectionFactory, fixes #142, obsoletes #125

[geek-merlin]

OPENEUROPA

Description

Running tasks from runner.yml creates a new process, with new config. It should not.
To keep BC, make it an option.

Change log

• Added:
  • RunInCurrentProcess task
  • Add an optional "in-current-process: true" key that enables that behaviour.
  • Readme docs

runner.yml example

commands:
  foo:
    tasks:
      - task: run
        in-current-process: true
        command: "drupal:drush-setup"

[geek-merlin]

Manually tested and worksforme:

I changed all run tasks in a complex runner.yml custom command to run-in-current-proces. The custom command worked the same way as before, and exec time went down from 38sto 16s.

Of course this is only a heuristic, tests for edge cases are still needed.

[geek-merlin]

Nope, i was too fast. Calling a custom command results in an endless loop, possibly due to global state.