Remove the build badge while we're waiting for the new VMs to be added to Travis
Removed breadcrumbId from everything and added idfa and idfv to all event calls
Default userId to IDFA if one isn't set
Incremented version number
Update README.md
Only change IDFA and IDFV if we're passing non-nil values.
If IDFA is not available, rely on the previously cached user ID if it exists. This is strictly for iOS 5 and below users.
Clean up project file