Added support for standard HTML controls

on PageReader Side
- Retrieve selected option in drop down by text / value
- Retrieve selected radio button in radio group (always by value)
- Check whether a radio group has a selected button or not

on PageWriter Side
- Select option in drop down by value / text
- Select radio button in radio group (always by value)

on ElementFinder

all TryFidnElements methods now have the possibilty to wait in seconds
in case the element is not available yet