* Use "const string&" rather than "string" in function calls when appropriate.
* Use "const Point3D&" instead of "Pint3D" in function calls when appropriate.
* Improved course calculation in calc_gc_course_dist()
* Safer thread handling code.
Vassilii Khachaturov:
Dont use "const Point3D&" for return types unless you're absolutely sure.
Erik Hofman:
* Use SGD_(2)PI(_[24]) as defined in simgear/constants.h rather than
calculating it by hand every time.
When you tune into a station start at a "random" point in the sequence.
Sped up the words per minute to 13 to which means one sequence per about 4 secs.
This means we get through the whole sequence in about 20 seconds leaving 10
seconds of silence.
