[gitignore] Add some more ignores to make life easy

Signed-off-by: Philippe De Swert <philippe.deswert@jollamobile.com>
[udev-util] Add some more functionality to udev-search

Signed-off-by: Philippe De Swert <philippe.deswert@jollamobile.com>
[udev] Try to do some $power_supply_path autodetection

Try to autodetect some useful paths if none is given, or it is not the
usual /sys/class/power_supply/usb one.

Signed-off-by: Philippe De Swert <philippe.deswert@jollamobile.com>