Refactorings on building the ApnsService
Supporting selectiveSend for variantID(s)
removed separation comment
Rename a variable + fixing typo
Fixing another typo
Adding more javadoc to files that have been touched for the PR
Merge branch 'SendToVariantIDs'
Merge remote-tracking branch 'upstream/master'
Add test utilities
Update license in AndroidVariantEndpointSpecification
Add InstallationRegistrationEndpointSpecification
Add PushNotificationSenderEndpointSpecification