Not able to build on Windows

Variable names in the script is preventing build on windows.

> uglifyjs $npm_package_main -cm -o $npm_package_minified_main -p relative --in-source-map ${npm_package_main}.map --source-map ${npm_package_minified_main}.map

fs.js:557
  return binding.open(pathModule._makeLong(path), stringToFlags(flags), mode);
                 ^

Error: ENOENT: no such file or directory, open 'C:\...\Forks\preact-router\${npm_package_main}.map'
    at Object.fs.openSync (fs.js:557:18)
    at Object.fs.readFileSync (fs.js:467:33)
    at Object.<anonymous> (C:\...\Forks\preact-router\node_modules\uglify-js\bin\uglifyjs:285:30)
    at Module._compile (module.js:573:32)
    at Object.Module._extensions..js (module.js:582:10)
    at Module.load (module.js:490:32)
    at tryModuleLoad (module.js:449:12)
    at Function.Module._load (module.js:441:3)
    at Module.runMain (module.js:607:10)
    at run (bootstrap_node.js:382:7)

related: #49

[ForsakenHarmony]

Yes, this is a known issue, if you are on windows 10 you can try bash for windows

(but that crashes when you run the tests)

[developit]

I’m not big on them. Rollup already supports 90% of what is needed here - for example, it can output gzipped bundle size. I’m just not using it properly 😛