Remove one more iOS 7 compile-time conditional.
Retry launching the tests three times.

Even twice is not sufficient, per https://travis-ci.org/inkling/Subliminal/jobs/16975689.
Slightly relax the uniformity requirement for Subliminal's test distribution.

The test has failed on Travis a couple of times, most recently
https://travis-ci.org/inkling/Subliminal/builds/16975672.
Merge pull request #110 from inkling/jeff/fix_build

Make one more iOS 7 CI change and fix the build.