adding ability to test ios-driver mobile safari with the python tests.

running the tests -
./go //py:mobileSafari_test:run
./go //py:mobileSafari_iPad_test:run

re-running a failed test (after you run and don't run 'go clean'):
build/python/bin/py.test build/lib/selenium/test/selenium/webdriver/mobileSafari/<test_file>_tests.py -k <test_method_name>

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adding tasks for compiling atoms for ios-driver