Add enablers for stopping sensors in suspend

Ambient light and proximity sensors are stopped before entering
late suspend.

Also fixes incorrect interpretation of initial PS value.

[mce] Add enablers for stopping sensors in suspend
Block late suspend while there are active alarm dialogs

Makes sure we keep sensors active etc while handling alarms.

[mce] Block late suspend while there are active alarm dialogs
Fix unlikely, but possible file descriptor leak
Disable building of unit tests

Changes to modules/display.c broke unit test compilation.
This must be reverted once the unit tests can be built again.
Merge pull request #90 from spiiroin/suspend_sensors

Enablers for stopping sensors before suspending