Merge pull request #113 from colemanw/master

Assign UI - Improve drag/dropping and handle undefined quantity
BUGFIX: Previously, newly added Needs received a visibility ID of NULL in the DB, despite having the "Public?" checkbox
checked. This caused two problems: (1) should the flexible need be made private, the sign up form would throw this
error: Project has no volunteer needs defined; and (2) user-added Needs would not appear in the dropdown unless the
user first unchecked then re-checked the "Public?" box.
Refactor dropdown in vol sign up form to use a more pure JS-based approach, as setting display:none on option elements doesn't work in all browsers.
Merge pull request #114 from fjg-conflux/signup_bugfixes

Signup bugfixes
Fix typo in comment; whitespace; resolve issue of required shift field when submitting to volunteer for a flexible need.
Merge pull request #115 from fjg-conflux/required_fields

Fix typo in comment; whitespace; resolve issue of required shift field w...
VOL-17 - Creating volunteer_role_id custom field to store roles in the Activity record.
Merge pull request #116 from davecivicrm/VOL-17

VOL-17 - Creating volunteer_role_id custom field to store roles in the A...
VOL-17 - set volunteer_role_id based on need, also fix duration/time_completed pair