Add a control wrapper to make logging more verbose

[ablaom]

Also, arrange for the final loss and training loss, when available, to be logged to Info at the default verbosity=1.

[codecov-commenter]

Codecov Report

Merging #43 (7884dde) into dev (d466526) will increase coverage by 1.64%.
The diff coverage is 96.66%.

@@            Coverage Diff             @@
##              dev      #43      +/-   ##
==========================================
+ Coverage   94.64%   96.28%   +1.64%     
==========================================
  Files           8        8              
  Lines         280      296      +16     
==========================================
+ Hits          265      285      +20     
+ Misses         15       11       -4     

Impacted Files	Coverage Δ
src/wrapped_controls.jl	91.66% <80.00%> (+1.34%)	⬆️
src/controls.jl	97.14% <100.00%> (+3.06%)	⬆️
src/train.jl	100.00% <100.00%> (ø)
src/composite_controls.jl	96.55% <0.00%> (+0.12%)	⬆️

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