fspath requires trailing slash

[carltongibson]

I used back ticks to set my fspath environment variable...

 export fspath=`pwd`

This results in a path without a trailing slash, something like...

/Users/davewiner/river4data

Running with such a path results in an error:

river4.js:1216
        for (var i = 0; i < list.length; i++) {
                                ^
TypeError: Cannot read property 'length' of undefined
    at .../river4/river4.js:1216:27
    at Object.oncomplete (fs.js:107:15)

I've not dug in but I'm guessing the path to the lists dir is generated something like: fspath + "lists".

Better would be to use path.join.

[carltongibson]

Closing this to clear up my console. Presume you have it covered. (Would fix and PR but toolchain is a little opaque.)