Fixed bugs in gwf-clean
Removed gwf-print-targets.

gwf -v will show the same relevant output.
Updated setup.py
* Changed graph.schedule, to accept a list of targets
* Added a graph.tasklist to return all tasks from a list of targets
* Added output of "running and skipped" tasks to gwf
* Changed the use of 'sets' to 'lists' in dependency_graph.py such that task lists are ordered in an optimal fashion, to reduce the amount of tests by the TaskScheduler
Merge branch 'develop' of github.com:dansondergaard/gwf into splitting-workflows
Changed gwf job indexes to be named "00001" and so fort.

Also,
gwf-status -j 2

is now similar to
gwf-status -j 00002

rm -rf ~/.gwf before using the changes in this commit
Changed the structure in how gwf is started.

All executions of gwf will start with a parsing and analysis of the workflow file.

These changes are made to prepare for clustering of tasks in PBS jobs.
Merge pull request #27 from runefriborg/develop

Fixes to prepare for splitting up workflows.