Remove threading, add DB permissions check, enable httpd

Moved to single thread to fix temp reading contention issues.
PWM from software is not reliable even with a high priority thread,
so it will need to move to hardware control.  For now it's
handled from the main thread which causes some latency when
there is scheduling starvation like durring high load or I/O
operations.

DB directory is now world r/w/x and DB file is world
readable.  Hopefully this will fix the contention issues with
simultaneous read access from apache.

Re-enabled the http server in the daemon on port 8888.