Adding a check for undefined before reading globalSettings.

The globalSettings variable was not defined when you chose to
volunteer for the opportunity. This sets it to an empty object.

Fixes #255
Fixed typo in name of preflight strategy.

contactTaskOwnersOnVolunteerEmail contained a preflight value
of preflightTaskVolunteerOwnerEmail. It should be
preflightTaskVolunteerOwner.
Merge pull request #256 from DavidEBest/devel-globalsettings-bug

Correcting a crash that occurs when volunteering for an opportunity.