Updates to build with stack and upstream changes

I figured this would be harder considering I haven't touched it in far
too long. Didn't take much work at all to get it built and running
again, and all tests (such as they are) pass.

+ stack didn't like the exe and test exe both using Main.hs
+ filled out other-modules in .cabal at stack's suggestion
+ EitherT is now ExceptT
+ pipes-concurrency deprecated `Unbounded` in favor of `unbounded`
+ tasty's wrapper of HSpec is now in IO
+ misc minor hLint changes

.gitignore

@@ -1,3 +1,4 @@
 cabal.sandbox.config
 .cabal-sandbox/
+.stack-work/
 dist/