removed set_locale to fix fscanf bug, when parsing in_accel_scale

set_local did modify the parsing of fscanf for floats i.e. "0.0000098" was parsed as "0,0000". This was not captured as error (zero scaling allowed?). For 0.0 scaling the orientation function does not work properly.

Fix: remove set_locale

Side effects: I haven't found any. The tests runs trough.

Solves or is maybe related to #333 (closed) #328 (closed)