Enter display off state after dimming

The logic inherited from N9 went to lpm_on state if low power mode
is enabled. This is not desirable because lpm display states require
locking of ui, which in turn cancels grace period that allows users
to get back to previously open application.

[mce] Enter display off state after dimming. Fixes JB#19192
Disable automatic dimming/blanking during incoming call

While there is an unanswered incoming call, power key can't be used
for display state control and therefore timer based dimmin/blanking
must not happen.

[mce] Disable automatic dimming/blanking during incoming call. Fixes JB#19194
Merge pull request #162 from spiiroin/incoming_call_blanking

Disable automatic dimming/blanking during incoming call
Merge pull request #161 from spiiroin/lpm_blanking

Enter display off state after dimming
Bump mce version to 1.30.1