Fix BasketLiquidation objective

[prism0x]

There are certain issues with limits in the BasketLiquidation objective:

• For some cases, the solver returns netflows where the liquidated amount is greater than the input basket amounts. This might be due to an issue with the upper limit.
• In the initializer, we should have i <= length(Δin)) instead of i < length(Δin)

It is intended to fix these in this PR.

[prism0x]

Here is a MWE to reproduce the issue

#=
# Liquidating a basket of tokens
This example illustrates how to use CFMMRouter.jl to liquidate a basket of tokens.
=#
using CFMMRouter
using LinearAlgebra

## Create CFMMs
cfmms = [
    ProductTwoCoin([14e3, 15e6], 0.99, [1, 2]),
    ProductTwoCoin([19e3, 11e6], 0.99, [1, 2]),
]

Δin = [0, 3000]

## Build a routing problem with liquidation objective
router = Router(
    BasketLiquidation(1, Δin),
    cfmms,
    maximum([maximum(cfmm.Ai) for cfmm in cfmms]),
)

## Optimize!
route!(router)

## Print results
Ψ = round.(Int, netflows(router))
println("Input Basket: $(round.(Int, Δin))")
println("Net trade: $Ψ")
println("Amount recieved: $(Ψ[1])")

#=
We can also see the list of individual trades with each CFMM:
=#
## Print individual trades
for (i, (Δ, Λ)) in enumerate(zip(router.Δs, router.Λs))
    tokens = router.cfmms[i].Ai
    println("CFMM $i:")
    println("\tTendered basket:")
    for (ind, δ) in enumerate(Δ)
        if δ > eps()
            print("\t  $(tokens[ind]): $(round(Int, δ)), ")
        end
    end
    println("\n\tRecieved basket:")
    for (ind, λ) in enumerate(Λ)
        if λ > eps()
            print("\t  $(tokens[ind]): $(round(Int, λ)), ")
        end
    end
    print("\n")
end

Without the fix, this computes:

Input Basket: [0, 3000]
Net trade: [32981, -45187377944]
Amount recieved: 32981
CFMM 1:
	Tendered basket:
	  2: 22618645921,
	Recieved basket:
	  1: 13991,
CFMM 2:
	Tendered basket:
	  2: 22568732023,
	Recieved basket:
	  1: 18991,