(bug 65309) check whether page already exist, code improvements

- check whether page already exist
- new core Bot style to handle options
- show options in doc string and with -help option
- new touch option to make a null edit on a page
- unicode strings for operator messages with variable contents

Change-Id: I2c574ace865ecc422524cd6682818297c326c750
Merge "(bug 65309) check whether page already exist, code improvements"