Restructure gem loading to reduce duplicate declarations and requires.  ...

...Enable single class usage w/o loading other classes.  Require all classes by requiring exact gem name.  My attempt at fixing issue #6.  There is still some copying and pasting required at the top of every file, but it is reduced to one line.  Individual classes can be loaded and used in isolation.

I changed the instructions from require 'sunlight/congress' to require 'sunlight-congress' too.  Not to be an enforcer but gem requires that don't match the gem name drive me nuts.  Also, it was a handy way to load everything.