about to change sequence_of_experiments to session
after renaming sequence_of_experiments to session, but before merging jacobs data exports and other improvements
admin enhancements not added yet
merged admin enhancements
updated app & project template
fixed crlf issue with bin\ptree (hopefully)
small bugfixes
merged with changes from upstream https://github.com/wickens/django-ptree.git
Fixed:  "Hide a session" (formerly, "Hide a sequence of experiments"): SessionParticipant objects (formerly "Participant in sequence of experiments") should be filtered as well.
"Categorize apps in the ModelAdmin": "Session" should be the first app on that page.
PTree Change List: fixed text clipping in cells, fit more text into the cells
Fixed a bug in 'Display app names without underscores'
"Categorize apps": If a section is empty, the header should be hidden too.