Add support for concolic execution

add comments

use measureIO on saving coverage

Fix mac builds with stack build in nix develop

calculate eventMap in mkWorld rather than giving it as an argument

sometimes contractNames are filepath:name, we have to account for that

hlint suggested eta reducing

Update filterFallbacks

Update filterFallbacks

Improve delay shrinking (crytic#1196)

hlint

models are separate, not consecutive

Speed up shrinking

Speed up shrinking

Speed up shrinking

incorporate runSymWorker into ui

runSymWorker

sym worker stops on its own when all the workers emit WorkerStopped

add SymExecCompleted; now normal workers will handle symexec worker's…

start with initial corpus

working implementation using queue

wip

wip

initial impl of runSymWorker

initial impl of runSymWorker

initial impl of runSymWorker

rename Echidna.Types.CodehashMap to Echidna.SignatureMapping

minor change to check if the failed test was a fluke

fix tests

fallback on bytecode metadata if findSrc doesn't work