Replace DifferentialEquations with DiffEqBase

Drop loading triggered by DifferentialEquations, use DiffEqBase

modified:   Project.toml
modified:   src/MechGluecode.jl

Reduced import for testing

modified:   Project.toml    0.1.51

modified:   test/plots_1.jl Reduced import

Plots and DiffEq ODE working and tested.

modified:   .gitignore  /.vscode

modified:   Project.toml Version, extras
modified:   README.md    First version
modified:   src/MechGluecode.jl  export norm
new file:   test/diffeq_1.jl    First version
new file:   test/diffeq_plots_1.jl First version
new file:   test/diffeq_plots_2.jl First version
new file:   test/plots_1.jl First version
modified:   test/runtests.jl Include all, comment snoopcompile