Bigger tests

gpaw/test/big/, doc/tutorials/

In these folders there are *agts.py scripts (advanced gpaw test system) that define workflows that we run when I remember to run them every weekend on the Niflheim supercomputer using MyQueue:

$ mq workflow -p agts.py .
Scanning 99 scripts:  |--------------------| 100.0%
Submitting 350 tasks: |--------------------| 100.0%

doc/tutorials/jellium/jellium.agts.py:

from myqueue.workflow import run

def workflow():
    """Run jellium tutorial and create fig2.png."""
    run(script='bulk.py', cores=4)
    with run(script='surface.py', cores=4, tmax='1h'):
        with run(script='sigma.py'):
            run(script='fig2.py')