Serialized preFetch calls #173

Enhanced preFetch error reporting

Updated to Quasar v0.17.14

Updated tools (specifying most important ones only): webpack v4.17.1, cssnano v4.1.0, html-minifier v3.5.20, http-proxy-middleware v0.19.0, mini-css-extract-plugin v0.4.2, register-service-worker v1.5.2, vue-loader v15.4.1, webpack-dev-server v3.1.7