`LoadError` when adding too many new cuts in an empty CutPruner

[frapac]

The use case is the following:

• I define a new CutPruner with a max cut set as 10:

man = CutPruner(AvgCutPruningAlgo(10), :Max)

• Then, I add 20 new cuts to this cut pruner:

addcuts!(man, A, b, mycut)

and it renders a LoadError

The problem is that you add directly 20 new cuts to an empty pruner which must store a maximum of 10 new cuts.
Thus, we enter in this loop:
https://github.com/JuliaPolyhedra/CutPruners.jl/blob/master/src/abstract.jl#L195

which calls gettrust in choosecutstoremove:
https://github.com/JuliaPolyhedra/CutPruners.jl/blob/master/src/abstract.jl#L93

As no cut is stored inside man, we have an empty trust, and we obtain an error when we want to select the cuts to keep:
https://github.com/JuliaPolyhedra/CutPruners.jl/blob/master/src/abstract.jl#L108