Modified quick and layout files so they are always in simulator-ui

I changed various places throughout the code so that files would always be stored in the simulator-ui folder (mainly this impacts the quick and layout files).  Previously these files would be stored relative to the working directory.  When running scripts through Nengo the working dir is simulator-ui, so everything worked fine.  But when running a script by itself (e.g. from command line/eclipse), it would create "quick" and "layout" folders wherever that script was run from.

I think the desired behaviour is just to have all these files in the same place, regardless of how the script is run.  However, it's possible that people like to have separate "quick" and "layout" folders, which is why I'm making this pull request.  So speak up if you don't want this changed!