fixing build, adding new configuration callbacks, basic checks against task requirements

Included in this pull request is:

* a fix to the build so the tests run again
* checks against the incoming requirements against internal resources (such as ram)
* removal of references to swap since the agent's model no longer contains information in swap
* removal of the old assign module
* configuration callbacks so change to `config["free_ram"]` or `config["cpus"]` will update the master