Otherwise it may still be doing it during ejection, resulting
in read IO errors in dmesg, which are harmless by themselves
but may confuse users.
Also tell udisks2 not to analyze disk by setting 'HintAuto'
property on BlockDevice object to 'false'
- Reduce platform specific code in ImageWriter class,
and move that to seperate classes.
- Use API calls to get current SSID on Windows and Linux instead
of launching command line utilities.
Only supported when NetworkManager is used on the Linux distro
as wpa_supplicant itself does not support reading PSKs through
DBus, only setting them.
Closes#457
