Add flaky.txt
Fix iOS common/element/button
Fix ios[common/helper]
Fix ios[ios/element/alert]
Fix ios[ios/element/textfield]
Update textfield and flaky.txt
Rewrite iOS support for appium 1.0
Update iOS support
Update ios_tests
Modern ruby defaults to utf-8
Update Rakefile
Ensure elements on iOS are visible
Update tests to meet new code requirements.

Removed test for mobile methods.
Removed test for execute_script (mobile methods are no longer advertised
and non-mobile don't work for Android).

Changed 'android' to :android' in `verify all attributes` as we now
symbolize keys.