ENH: Added video file exists check
Merge branch 'master' of https://github.com/isolver/psychopy
Merge branch 'master' of https://github.com/isolver/psychopy
Merge branch 'master' of https://github.com/isolver/psychopy
Merge branch 'master' of https://github.com/isolver/psychopy
DEP: psutil 2.x is now expected depend.

for all OS's
all iohub kb key mapping issues fixed on windows

'all issues' meaning all that are known of naturally. ;)
iohub Computer variable name cleanup, +

+ started iohub Computer class tests
+ added suggested replacement for skip_under_travis imp.
Merge branch 'master' of https://github.com/isolver/psychopy
BF: iohub kb keys on linux
- mods now labeled correctly
- control keys OK

Numlock key and char values need to be sorted out; inconsitant mapping with other OS's
ENH: iohub keyboard event mapping complete.
Merge branch 'master' of git://github.com/psychopy/psychopy
BF: comment cleanup in demo
Merge pull request #689 from isolver/master

iohub updates