Breaking changes for MOI 0.10

[odow]

More test failures than we should be happy with. I'll comment in-line.

[codecov]

Codecov Report

Merging #219 (d23938f) into master (e31b30c) will decrease coverage by 2.04%.
The diff coverage is 91.44%.

❗ Current head d23938f differs from pull request most recent head 7f9984c. Consider uploading reports for the commit 7f9984c to get more accurate results

@@            Coverage Diff             @@
##           master     #219      +/-   ##
==========================================
- Coverage   87.32%   85.27%   -2.05%     
==========================================
  Files           8        7       -1     
  Lines         418      292     -126     
==========================================
- Hits          365      249     -116     
+ Misses         53       43      -10     

Impacted Files	Coverage Δ
src/SCS.jl	77.77% <ø> (+2.77%)	⬆️
src/linear_solvers/direct.jl	85.71% <ø> (ø)
src/linear_solvers/gpu_indirect.jl	0.00% <ø> (ø)
src/linear_solvers/indirect.jl	100.00% <ø> (ø)
src/MOI_wrapper/MOI_wrapper.jl	86.80% <90.58%> (-5.63%)	⬇️
src/MOI_wrapper/scaled_psd_cone_bridge.jl	91.07% <91.07%> (ø)
src/c_wrapper.jl	88.70% <100.00%> (ø)

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[odow]

Okay, after this experience, I think I'm now on board with:

1. The required bridges thing. It made SCS much simpler than the direction I was originally going down.
2. The OptimizerCache stuff. Not necessarily as a replacement layer, but as a simpler way of converting into matrix-type formats
3. The one-shot optimize!(dest, src).

All-in-all, this rewrite of SCS.jl was not a fun experience, but I think we're in a much better place than we were.

[odow]

@blegat did you actually try jump-dev/MathOptInterface.jl#1592 on a solver? It isn't working.

[odow]

empty! is not reaching the inner optimizer

julia> model = MOI.Bridges.full_bridge_optimizer(
           MOI.Utilities.CachingOptimizer(
               MOI.Utilities.UniversalFallback(MOI.Utilities.Model{Float64}()),
               SCS.Optimizer(),
           ),
           Float64,
       );

julia> MOI.set(model, MOI.Silent(), true)

julia> x, ci = MOI.add_constrained_variables(model, MOI.Nonnegatives(2));

julia> MOI.optimize!(model)

julia> MOI.empty!(model)

julia> MOI.get(model, MOI.TerminationStatus())
OPTIMAL::TerminationStatusCode = 1