Bumped version to 5.1.5 (515)
Bumped version to 5.1.5 (515)

Change-Id: I50edfe301e8f56bb02e5fd697fc1c2b81e1b7070

jarekankowski/iosched,jarekankowski/iosched,WeRockStar/iosched,WeRockStar/iosched,WeRockStar/iosched,jarekankowski/iosched