healthd: Detect power supply type for all charger devices

Power supply type is not determined via the device name,
hence iterate over all available devices in the subsystem
node and read the type from device file.

  shell@hammerhead:/ $ ls /sys/class/power_supply
  ac
  batt_therm
  battery
  touch
  usb
  wireless

<4>[ 3184.867782] healthd: touch: Unknown power supply type
<4>[ 3184.868039] healthd: batt_therm: Unknown power supply type
<6>[ 3184.880506] healthd: battery l=89 v=4181 t=25.5 h=2 st=2 c=-288 chg=u
<4>[ 3184.890362] healthd: touch: Unknown power supply type
<4>[ 3184.890549] healthd: batt_therm: Unknown power supply type
<6>[ 3184.899419] healthd: battery l=89 v=4181 t=25.5 h=2 st=2 c=-59 chg=u
<4>[ 3184.908756] healthd: touch: Unknown power supply type
<4>[ 3184.908984] healthd: batt_therm: Unknown power supply type
<6>[ 3184.919672] healthd: battery l=89 v=4181 t=25.6 h=2 st=2 c=-25 chg=u

Change-Id: I863bfab95193899460237b51997e0418eeb4ee2c
adb: host: Provide better sideload status

 * Show data transfer in MB and in multiple of the file size.

 * Show a spinner to indicate liveness, which is updated at least once
   per second regardless of data transfer.

 * Do not allow sideload of zero sized files.

Change-Id: I1bd0df6a8183fad5a502fc26a7e789c27d24f71a