Fixed broken npm install on Windows

[duluca]

Current Behavior

npm install fails on Windows, because rm -rf doesn't exist. When that issue is resolved, dist/testdouble.js fails to generated, because Windows can't parse $npm_package_config_build_file.

Expected Behavior

npm install works on Windws.

Changes made

[x] Replaced rm -rf with rimraf on the clean script
[x] Added cross-conf-env to compile:browser step, so $npm_package_config_build_file is interpreted correctly

Future suggestion

• version:write and version:changelog may also benefit from cross-conf-env

[searls]

Would you mind re-working this without the changes to the indentation/formatting of the package.json?

[duluca]

@searls Didn't mean to change the formatting, rolled it back

[searls]

Thanks! I think the same applies to the other PR you started. I hope to find some spare time to look at it soon, but if you start chipping away some of the tsc errors, that'd be great too.