Parallelized multi_scan and bug fixes

Run your tests in a balanced manner across multiple parallelly running iOS Simulators using the parallel_testrun_count option. (#107 ).

Fixes (#50 ) where skipped tests were removed when batching.

Fixes (#75 ) by allowing a String or an Array of tests that should be skipped.

Fixes (#41 ) to support the skip_build option properly.

Adds support (#92 ) adding skipped tests to junit reports.

Updates to use the latest xctest_list so that testcases named test can be found.