HAL_Linux: make I2CDriver more portable

this allows it to build on the Beaglebone
HAL_Linux: default to hal.console on stdout
AP_Menu: copy with newline from console

helps debugging on HAL_Linux
AP_Menu: be friendly to multi-tasking OSes in menus
HAL_Linux: fixed scheduling priorities

need to be between 1 and 99
Plane: moved Linux logs to logs directory
SITL: added a SIM_GPS_HZ option

this allows simulation of slow GPS updates (for example, the 1Hz GPS
problem)