Fix crash with appendDataToBuffer appending a nil NSString
[refactoring] Move all interactions with simulator to Simulator* classes.

Summary:
Introducing 3 new classes that encapsulates interaction with simulator apis:
1) SimulatorInfo - for retrieving simulated device information, like architecture, device family, sdk version. Also this class could be used to retrieve available devices, sdks and etc.
2) SimulatorUtils - provides methods to kill all simulator processes and to clean simulator data.
3) SimulatorWrapper - encapsulates installation and uninstallation of applications. Also provides convenient method to run tests.
Merge pull request #370 from Zehhu/data_to_buffer_crash

Fix crash with appendDataToBuffer appending a nil NSString
Record stderr of sim during testing and print it contents in log if it fails.
Merge pull request #372 from facebook/nekto/simulator_wrapper

[refactoring] Move all interactions with simulator to Simulator* classes
Removed "-simulator" option.
Improve JUnit output by printing all test exceptions and not only first one
Add reporter for TeamCity
Remove unused code
Add escaping
Fix indent
Merge pull request #373 from facebook/nekto/improve_logging_errors

Record stderr of sim during testing and print it contents in log if it fails.
Merge pull request #371 from acoomans/deprecate_simulator_option

Deprecate old option `simulator` in xctool.
Merge pull request #377 from facebook/nekto/improve_junit_output

Improve JUnit output by printing all test exceptions and not the only first one
Add reporter to readme
Add reporter to readme
Merge pull request #379 from AutoScout24/reporter-teamcity

TeamCity reporter
Fix readme typo
Fix for "Removed "-simulator" option." (5a3b901)
Fix SDK finding regex