Fix for npm install

I'm a newbie with Node.js, but the change in this pull request fixed the following problem:

    inpakro39691:npmap.js regan_sarwas$ npm install
    npm ERR! Error: Invalid Package: expected leaflet-markercluster but found leaflet.markercluster
    npm ERR!     at /usr/local/lib/node_modules/npm/lib/cache/add-local-tarball.js:161:14
    npm ERR!     at process._tickCallback (node.js:419:13)
    npm ERR! If you need help, you may report this *entire* log,
    npm ERR! including the npm and node versions, at:
    npm ERR!     <http://github.com/npm/npm/issues>

    npm ERR! System Darwin 13.2.0
    npm ERR! command "node" "/usr/local/bin/npm" "install"
    npm ERR! cwd /Users/regan_sarwas/WebDev/npmap.js
    npm ERR! node -v v0.10.29
    npm ERR! npm -v 1.4.14
    npm ERR! 
    npm ERR! Additional logging details can be found in:
    npm ERR!     /Users/regan_sarwas/WebDev/npmap.js/npm-debug.log
    npm ERR! not ok code 0