BF: Many fixes to (very) broken Builder use of MultiStairHandler and its data outputs

Builder couldn't use it at all, but also the experiment (wideText) outputs
were lacking lots of info about the trials.


Squashed commit of the following:

commit 205b25bd3d62216a3b954cac2e2039925460aa18
Author: Jon Peirce <jon.peirce@gmail.com>
Date:   Wed Aug 21 17:51:52 2013 +0100

    BF: final fixes to MultiStairHandler data outputs and added tests

commit 2b7364fd275035067289fd297e9b0dd96d5735d7
Author: Jon Peirce <jon.peirce@gmail.com>
Date:   Wed Aug 21 16:55:44 2013 +0100

    BF: further fixes to the MultiStair and StairHandler for wide-text data outputs

commit 87319c6cf523f4bcd1e3cd789e16312b751a4219
Author: Jon Peirce <jon.peirce@gmail.com>
Date:   Wed Aug 21 11:59:30 2013 +0100

    BF: further improvements to data saving (wide text) from multistair

commit f61c3ad444cf9e59f2f5b98903c8781aaaa9a819
Author: Jon Peirce <jon.peirce@gmail.com>
Date:   Fri Aug 16 17:42:24 2013 +0100

    BF: 'interleaved staircases' loop now correctly loading/storing conditions file info

    BUT not storing the additional staircase.otherData correctly

    Conflicts (trivial):

    	psychopy/app/builder/experiment.py

commit 5978afa79cd457da1601ca041098ea383106ff28
Author: Jon Peirce <jon.peirce@gmail.com>
Date:   Thu Aug 15 11:57:24 2013 +0100

    in progress: working on fixing the probs with MultiStair option in builder loops