Fixed: CPTextField doesn't update its style when editing

Previously, the update of the style of an editing textField didn't work.
Now when editing, we can update the font, color, alignment and vertical-alignment of the textField

Test app in Tests/Manual/CPTextFieldEditingStyleTest/

Fixed #2057
Fixed: textField in CPTextFieldTest doens't have a placeholder
Fixed: setTextColor of CPTextField changed the color of the placeholder

Previously, the method setTextColor changed the color of the placeholder as well.
Now it doesn't as in cocoa

Test app in Test/Manual/CPTextFieldEditingStyleTest
Merge pull request #2134 from Dogild/CPTextFieldEditingStyle

Fixed: CPTextField doesn't update its style when editing [+1]