Prepare for more development
Add ruby 2.0.0 to TravisCI testing.
Make list of supported rubies in readme more readable.
DueBadges: keys for by_member are now the member's id not name
Register and subclasess now use symbols not strings for attendance state. closes #65
Add present_on? and absent_on? methods to Register::Attendance
Add allow_booking attribute to Event. closes #52
Add myscout_programme_times attribute to Section. closes #67
Add handling of a cost of "TBC" to Event. closes #69
Prepare for release
Merge branch 'staging'