Bind fetch to window

[mzgoddard]

I fixed up @rub1e's #232 solution for #230. I amended the commit so credit can go where it's due. There was an extra parentheses that created an error in the typescript compiler and the linter error was rendered on the wrong line in github.

I found the cause of the issue.

The typescript transpilation rewrites the import of the local fetch module to a commonjs require.

var fetch_1 = __importDefault(require("./fetch"));

When transpiled src/run_action.ts

    fetch(url, options)

translates to this line in lib/run_action.js

    fetch_1.default(url, options)

and so the window fetch method is called on fetch_1 as it's this.

[rub1e]

Cheers mate - I had a reminder to come back and figure out what was going on here - you've saved me the bother!!