Improves the APIs for various prebuilt subsystems (PIDSubsystem, TrapezoidProfileSubsystem, ProfiledPIDSubsystem). Addresses #2128, and also changes the rather cumbersome getSetpoint API to a more intuitive setSetpoint one. Updates examples to match.
Since there is a new version of GearsBot using the new command-based
API, the old GearsBot is just removed.
PR #1842 is being included to verify this PR is correct.
The old headers were moved into folders because doing so avoids polluting
the system include directories.
Folder names were also normalized to lowercase.
Instead of defining NAMESPACED_WPILIB to remove the "using namespace frc"
shim in Base.h, instead require NO_NAMESPACED_WPILIB be defined to add it.
Fix up various examples to use correct namespacing.
