Add datetime and opensesame version and codename as experiment variables.
Unbreak external runner
Update default template
Do not use keywords for `decode()` to maintain compatibility with Python < 2.7
added stub="" to default form for form_text_input item
Initial migration towards `osexception` Exception handling
Fix broken copy-file-to-pool functionality
Also catch exceptions during get_ready() phase
Restructuring of multiprocess runner
Fix check for logfile writability
Fix double spacing after line wrapping (fixes #203)