Enhanced default_poll function

This compensates for the fact that some pgrep implementations (such as
busybox-pgrep) sometimes match against the full path of programs, (i.e.
"/usr/sbin/wpa_supplicant" instead of just "wpa_supplicant")
Custom polling function for dbus

This checks for "dbus-daemon" instead of simply "dbus".

Another way would be to rename the dbus daemon to "dbus-daemon", but I
chose to do this for backwards compatibility

Thanks to Mr. Green for making me aware that the existing implementation
wasn't accurate.