build.sh improvements

- run `go test ./...` and STOP on error
- run `go build` and STOP on error
- run `go install` and STOP on error

scripts/build.sh

@@ -15,9 +15,30 @@ cd lib/renderer
 mewn
 cd ../..
 
-echo "**** Installing Wails locally ****"
+echo "**** Checking if Wails passes unit tests ****"
+if ! go test ./...
+then
+    echo ""
+    echo "ERROR: Unit tests failed!"
+    exit 1;
+fi
+
 cd cmd/wails
-go install
+echo "**** Checking if Wails compiles ****"
+if ! go build .
+then
+    echo ""
+    echo "ERROR: Build failed!"
+    exit 1;
+fi
+
+echo "**** Installing Wails locally ****"
+if ! go install
+then
+    echo ""
+    echo "ERROR: Install failed!"
+    exit 1;
+fi
 cd ../..
 
 echo "**** Tidying the mods! ****"