* Check for masked packages in the --resume merge list and bail

* Check for masked packages in the --resume merge list and bail
  out in that case (bug #199408).

* In depgraph.loadResumeCommand(), create a dependency graph from
  the resume list. This ensures that the merge list has it's
  dependencies satisfied. It also enables --tree display together
  with --resume.

* Fix --resume mode to check for unsatisfied blockers and bail out when
  necessary.

* Add --nodeps to the parallel-fetch --resume options since recalculation of
  deps is a a waste here.

* Delete the resume list(s) if there is an unsatisfied block.

(trunk r10113:10117)

svn path=/main/branches/2.1.2/; revision=10118