Change underscore import/export boiler plate

[megawac]

Fixes #186

Lets you do

var _ = require("underscore-contrib/underscore.object.selectors");

PS I would also like to remove the underscore.* prefixes

[joshuacc]

@megawac This looks good to me.

I have no objection to removing the prefixes. Maybe do that in a separate commit, though?

Also, I see that @fogus took my suggestion of adding you as a collaborator. :grin: Feel free to merge this in at any time.

[joshuacc]

:+1: