Merge pull request #406 from philippwiesemann/master

ENH: Fix help button alignment in Builder dialogs
BF: sensible loading of mono sound files in SoundPyo; closes #408
ENH: smoother mono sound-file playing as stereo (pyo)
Merge pull request #409 from jeremygray/master

BF: better handling of mono sound files in SoundPyo; closes #408
BF: fixed further problem with ImageStims appearing grey in certain cases

Only if they had a size being set, and an image being set initially to "sin"
BF: allow lists of key presses to be considered correct in Builder
Merge pull request #410 from ianhussey/master

BF: allow lists of key presses to be considered correct in Builder
Fix ValueError in keyboard component output code

Running an experiment from the Builder view using a keyboard component
raised a ValueError because a format string had an error in its syntax.