[RDY] Pixel offset

It looks like the infowindow offset problem came up with the [small markers build](https://github.com/AgileVentures/LocalSupport/pull/102). The [custom builder](http://apneadiving.github.io/) example in apneadiving's code sample page seems to suggest that the best way to handle the finer points of managing custom markers and custom infowindows is in conjunction with other 3rd party libraries for the google maps api. This is our first attempt to assemble something similar to what he demonstrates. 

I setup bower so that we can pull in one-off scripts in more easily and not have it added to version control.


[Staged here](https://gmaps-upgrade.herokuapp.com/). I had to tell heroku to use multiple buildpacks with `heroku config:add BUILDPACK_URL=https://github.com/ddollar/heroku-buildpack-multi.git`, and then I specified a node buildpack before my ruby one in `.buildpacks`. In the node build on heroku, it will do a `npm install`, which leads to a `bower install`, which pulls in the 3rd party scripts before the ruby build does `rake assets:precompile`. I'm not sure what hacks will be necessary for ninefold.