Remove skips from tests before checking in CI

This is a bit gross, but I think optimizing for the end users is important enough to justify the dance.

bin/build.sh

@@ -41,7 +41,7 @@ do
   exercise_name=$(basename $example_file .example.elm)
   cp "$exercise_dir/$exercise_name.example.elm" "build/$exercise_name.elm"
   cp "$exercise_dir/tests/elm-package.json" build/tests/
-  cp "$exercise_dir/tests/Tests.elm" build/tests/
+  cat "$exercise_dir/tests/Tests.elm" | sed 's/skip <|//g' > build/tests/Tests.elm
 
   echo '-------------------------------------------------------'
   echo "Testing $exercise_name"

package.json

@@ -1,6 +1,5 @@
 {
   "scripts": {
-    "postinstall": "elm package install -y",
     "test": "elm-test"
   },
   "dependencies": {