The non-NT portion has been moved to wpiutil.
The NT portion has been moved to ntcore (as NTSendable).
SendableBuilder similarly split and moved.
SendableRegistry moved to wpiutil.
In C++, SendableHelper also moved to wpiutil.
This enables use of Sendable from wpimath and also enables
moving several classes from wpilib to wpimath.
This makes code easier to read and more consistent between C++ and Java.
Also update clang-format settings to always add a line break (even if no braces are used).
- Remove use of std::set. The only place std::set was actually used was in ParallelRaceGroup,
but this was of minimal utility as ParallelRaceGroup checked for duplicate subsystem
requirements, so it would be very unusual to end up with duplicate commands
in any case; replaced it with a vector.
- Remove use of std::unordered_map except for SelectCommand. Replaced with vector.
- Use pImpl idiom for CommandScheduler
- Minimize include files (remove unnecessary ones)
- Reformat include file order for consistency
