Removed @todo.

  This is managed now by improved error handling.

	modified:   drushsubtree.drush.inc
Stub out new validation checks.

  Run checks on hook_buildmanager_build.

	modified:   drushsubtree.drush.inc
Added subtree-dev-checks flag.

  Flag is available for buildmanager build. Runs helper checks and offers
  info and suggestions to developers during (re)build.

	modified:   drushsubtree.drush.inc