ENH: allow the psychopy app to --run a python script without loading the app interface
BF: rename _ as _junk when not intended as translation function _( )

- need to avoid name collision in the app: use of _ to mean junk when unpacking tuple, vs global translation function
- only preferences.py should actually matter, maybe info.py (because the translation function is for the app, not user scripts)
- but change everywhere to be consistent

$ find ../.. -name '*.py' | xargs -n 1 python gg_.py > gg_out.txt

# where gg_.py is:
import re, sys
exp = re.compile(r'\b_\b[^\(]')
print sys.argv[1], '---------'*4
for i,line in enumerate(open(sys.argv[1]).readlines()):
  if exp.search(line):
    print i+1, ':', line,
BF: MultiStairHandler was running over by one trial on each stair

It needed to test whether the staircase had finished (not at the point
of the next trial starting but at the end of the previous).

Also added a test to the suite to catch this in future
FF: trying to fix travis issue with commit 5712203561

Travis running the test suite fails to create an app. I'm guessing that
travis has '--run' or '-r' in its calling args and the app now treats
these as saying "run file don't load app"
Revert "ENH: allow the psychopy app to --run a python script without loading the app interface"

This reverts commit 5712203561b461f62b4188fc4bed7372b8193162.
Revert "FF: trying to fix travis issue with commit 5712203561"

This reverts commit cf366fc8d18e3ee85d7d999f233d881c3dab2a19.
Merge branch 'master' of git://github.com/psychopy/psychopy
BF: Fixed process priority setting for linux
ADD: iohub keyboard tests starting point
Merge pull request #682 from isolver/master

ADD: iohub keyboard tests starting point