add data optimizers

[joaquimg]

Add data optimizers, useful for educational purposes.
Students can implement their own simplex method, interior point, b&b and so on.

[joaquimg]

cc @guilhermebodin

[guilhermebodin]

Nice one!

[codecov-io]

Codecov Report

Merging #102 into master will decrease coverage by 2.16%.
The diff coverage is 76.64%.

@@            Coverage Diff             @@
##           master     #102      +/-   ##
==========================================
- Coverage   90.29%   88.12%   -2.17%     
==========================================
  Files          12       14       +2     
  Lines        1339     1381      +42     
==========================================
+ Hits         1209     1217       +8     
- Misses        130      164      +34

Impacted Files	Coverage Δ
src/generic_optimizer.jl	0% <0%> (ø)
src/mockoptimizer.jl	91.07% <100%> (+7.4%)	⬆️
src/LinQuadOptInterface.jl	98.41% <100%> (ø)	⬆️
src/generic_model.jl	82.75% <82.75%> (ø)
src/solver_interface.jl	58.33% <0%> (-8.34%)	⬇️
src/constraints/scalaraffine.jl	94.44% <0%> (-1.34%)	⬇️
src/constraints/vectoraffine.jl	94.68% <0%> (-1.02%)	⬇️
src/constraints/singlevariable.jl	97.18% <0%> (+0.72%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 82246f7...44e85ba. Read the comment docs.

[joaquimg]

case study: https://github.com/joaquimg/RationalSimplex.jl/blob/master/src/MOI_wrapper.jl