make after_save hooks more robust
properly restore columns if migration is reverted.
Merge branch 'master' of manno.name:frab into conference_days

Conflicts:
	app/models/event_person.rb
make availability migration more robust
make bundle update work
clean up permissions for reviewers
Merge branch 'conference_days' of manno.name:frab
fix error on new rails?
get rid of therubyracer, use native nodejs instead. Works on more platforms.
static twitter bootstrap 1.4 files
remove unused database tables
remove conference acronym from top navigation
Update Gemfile.lock
Update DB schema
Fix include of bootstrap JS lib
Update .gitignore
Fix off-by-one in max timeslot selection
Fix users not being deleted with persons and display of versions for deleted users
Add to_s to Day
Fix event reports