Add textfield_named for iOS

Fix #100

lib/appium_lib/ios/element/textfield.rb

@@ -64,4 +64,14 @@ def textfield_include text
   def textfield_exact text
     xpath "textfield[@text='#{text}']"
   end
+
+  # Get the first textfield that exactly matches name
+  # @return [Element]
+  def textfield_named target_name
+    wait do
+      target = e_textfields.detect { |e| e.name == target_name }
+      raise "Textfield named #{target_name} not found" unless target
+      target
+    end
+  end
 end # module Appium::Ios

lib/appium_lib/ios/helper.rb

@@ -193,6 +193,8 @@ def id id
     find_element :id, id
   end
 
+  # Return the iOS version as an array of integers
+  # @return [Array<Integer>]
   def ios_version
     ios_version = execute_script 'UIATarget.localTarget().systemVersion()'
     ios_version.split('.').map { |e| e.to_i }