When a battery is not present, due to the fact that we always set fACConnected
for it to true to enable boot without batteries, the tracker cannot rely on
the fACConnected flag alone.

Thus, check also that the battery is marked as present.
fix issue #3(deadlock) and issue #4(quick poll after AC change)
bump version v1.52
Merge branch 'master' of https://github.com/jafd/OS-X-ACPI-Battery-Driver
update changelog for v1.51 and v1.52