Use seperate thread for signal handler and...
- use specific RT signal for UART
- block uart signal in main thread and allow it in reading thread.
Get back to poll functionality.
Do uart reading in run_sensors
Uart reading using epoll because it should be faster.
Use line triggered mode
Return result of poll.
Merge branch 'epoll' into dev

Merged with epoll version for easier start.
Test epoll with level triggered approach.
Try with blocking read
Test with higher baudrate and single thread epoll.
Merged dev branch
Resolved bugs by testing.
Added LISA_INDEX_MSG_LENGTH
Completed debug message.
Added difference between debug and release version
Clean up.
Allowing bigger debug messages.
Change comment.
Changed Max limit for protobuf messages
add some debugging info to run_piksi
Merge branch 'dev' to master