Update license

GPLv3 is recommended for Foreman plugins
Merge pull request #30 from pitr-ch/master

minor improvements, pls see commit messages
Update readme
Automatic commit of package [rubygem-foreman-tasks] release [0.3.0-1].
Add link to issue tracker
Require dynflow >= 0.5.0
Automatic commit of package [rubygem-foreman-tasks] release [0.3.1-1].
Fix adding links to related resources

We REALLY need adding tests into this repo to avoid this regressions.
Automatic commit of package [rubygem-foreman-tasks] release [0.3.2-1].
Make sure `require_dependency` is called only once for every action

Otherwise, issues with type mismatch appear, when the old class
is still around while calling the require_dependency.

The classes are reloaded in `world.reload!`.
Merge pull request #32 from iNecas/fix-reloading

Make sure `require_dependency` is called only once for every action
Automatic commit of package [rubygem-foreman-tasks] release [0.3.3-1].
Extract transaction checking

Makes it easier to stub it when this check is not needed (e.g. in tests)
Merge pull request #33 from iNecas/extract-check-transaction

Extract transaction checking
Automatic commit of package [rubygem-foreman-tasks] release [0.3.4-1].
Extracting ActionTriggering form ActionSubject module

to be able to create resources acting as subjects without triggering
and the other way around