More logging color tweaks.

Yellow looks bad on white, and blue looks meh on black. So stop coloring info
lines, stop using yellow, and only use blue for the header part.
Implement package-level shared variables for CoffeeScript.

CoffeeScript doesn't allow you to assign to global variables using variable
assignment syntax (though you can assign properties to the global object), which
is the way to create package-level shared variables in Meteor. This commit
provides a CoffeeScript-specific to share variables between files in a package
without adding a redundant alternative for JavaScript files: simply assign
properties on the symbol `shared`.