Position and width

The patch adds options for setting window position and width.

Please note that for the 5.0 version, the width parameter is '-z' to avoid conflict with '-w windowid'. If this change is not desired, the 4.7 version applies fine, but '-w windowid' will not work. This change was carried on through the 5.2 version, necessitated by failure of the 5.0 version on dmenu-5.2, hence -z is now the only option to preserve the '-w windowid' function.