Thread/Mutex: move attributes up
Thread: explicitly delete the copy constructor/assignment

Don't use the obsolete NonCopyable class.
Thread/PosixMutex: relicense to BSD 2-clause

This is pretty trivial code, and I'm effectively the only copyright
holder.
dlgTarget_L.xml: Help text for ETE.
RoutePolar: Optimized Initialise() method

The IndexToAngle() function performed a division, a multiplication and
a substraction for every call in the for loop of the Initialise() method.
This could be reduced to one constexpr constant and one substraction for
each iteration.