Fixed several cosmetic code issues. Improved detection of same/different disk detection. Switched shared_ptrs to use std implementation instead of boost one. Cleaned up includes in headers. (CH-259)
Changed standard message boxes displayed when shell extension is not registered or version does not match to resizable message box with checkbox "Do not show this again". That allows to get rid of the annoying messages with each launch of ch when user does not want to register the extension (CH-67).
Resizable message box: applied minimum size limit to the dialog box and adjusted the default layout to work properly for simple one line message boxes (CH-67).