FS dependency causing issues on Windows

Hi team,

Am currently trying to use as require('backstopjs') but finding the lib wont work due to dependency on 'fs' (for Mac I assume).

Using

- windows 7
- ` "devDependencies": {
"babel-cli": "^6.26.0",
"babel-core": "^6.26.0",
"babel-loader": "^7.1.4",
"babel-preset-env": "^1.6.1",
"babel-preset-react": "^6.24.1",
"babel-preset-stage-2": "^6.24.1",
"react-hot-loader": "^4.0.0",
"webpack": "^4.1.1",
"webpack-cli": "^2.0.12",
"webpack-dev-server": "^3.1.1"
},
"dependencies": {
"backstopjs": "^3.1.19",
"react": "^16.2.0",
"react-dom": "^16.2.0",
"toastr": "^2.1.4"
}`

Compiling failing due to the following:

`ERROR in ./node_modules/backstopjs/core/util/extendConfig.js
Module not found: Error: Can't resolve 'fs' in 'C:\Users\txxxxxx\Desktop\backstopApp\ui-regression\node_modules\backstopjs\core\util'
@ ./node_modules/backstopjs/core/util/extendConfig.js 3:9-22
@ ./node_modules/backstopjs/core/util/makeConfig.js
@ ./node_modules/backstopjs/core/runner.js
@ ./src/index.js
@ multi (webpack)-dev-server/client?http://localhost:8080 webpack/hot/dev-server react-hot-loader/patch ./src/index.js

ERROR in ./node_modules/temp/lib/temp.js
Module not found: Error: Can't resolve 'fs' in 'C:\Users\txxxxxx\Desktop\backstopApp\ui-regression\node_modules\temp\lib'
@ ./node_modules/temp/lib/temp.js 1:11-24
@ ./node_modules/backstopjs/core/util/extendConfig.js
@ ./node_modules/backstopjs/core/util/makeConfig.js
@ ./node_modules/backstopjs/core/runner.js
@ ./src/index.js
@ multi (webpack)-dev-server/client?http://localhost:8080 webpack/hot/dev-server react-hot-loader/patch ./src/index.js

ERROR in ./node_modules/temp/node_modules/rimraf/rimraf.js
Module not found: Error: Can't resolve 'fs' in 'C:\Users\txxxxxx\Desktop\backstopApp\ui-regression\node_modules\temp\node_modules\rimraf'
@ ./node_modules/temp/node_modules/rimraf/rimraf.js 6:9-22
@ ./node_modules/temp/lib/temp.js
@ ./node_modules/backstopjs/core/util/extendConfig.js
@ ./node_modules/backstopjs/core/util/makeConfig.js
@ ./node_modules/backstopjs/core/runner.js
@ ./src/index.js
@ multi (webpack)-dev-server/client?http://localhost:8080 webpack/hot/dev-server react-hot-loader/patch ./src/index.js`

If I set webpack.config.node.fs as 'empty', I no longer get the errors (obviously) but the browser runs into errors, so wondering if FS isnt optional or similar?

Please let me know if I can provide more info.