Now, implicit narrowing conversions are only used with wpi::Now(). This
also fixes clang-tidy warnings about C-style casts. For example:
```
== clang-tidy /__w/allwpilib/allwpilib/wpilibNewCommands/src/main/native/include/frc2/command/SwerveControllerCommand.inc ==
/__w/allwpilib/allwpilib/wpilibNewCommands/src/main/native/include/frc2/command/SwerveControllerCommand.inc:95:18: warning: C-style casts are discouraged; use static_cast/const_cast/reinterpret_cast [google-readability-casting]
auto curTime = units::second_t(m_timer.Get());
^
```
In that case at least, the cast was removed entirely since Get() already
returns a units::second_t.
* Replace Matrix<> with Vector<> where vectors are explicitly intended.
I found these via `rg "Eigen::Matrix<double, \w+, 1>"`.
* Pass all Eigen matrices by const reference. I found these via `rg
"\(Eigen"` on main (the initializer list constructors make more false
positives).
* Replace MakeMatrix() and operator<< usage with initializer list
constructors. I found these via `rg MakeMatrix` and `rg "<<"`
respectively.
* Deprecate MakeMatrix()
Also refactored RKF45 implementation to match the new style, which is
easier to read.
The tests were switched from RKF45 to RKDP since it's more accurate.
Using the plant output means that measurement noise can be incorporated.
SingleJointedArmSim (in C++ and Java) and ElevatorSim (in C++) used the
state instead of the measurement.
Closes#3042
Some vestigial functions were never removed, and C++ single-jointed arm
sim was missing a flag for disabling gravity simulation. This is useful
for mechanisms like turrets.
Fixes#2738.
This includes physics simulation support for arms/elevator models, as well as differential drivetrains.
Swerve might be added at a later date.
Co-authored-by: Claudius Tewari <cttewari@gmail.com>
Co-authored-by: Prateek Machiraju <prateek.machiraju@gmail.com>
Co-authored-by: Tyler Veness <calcmogul@gmail.com>
