Update cepl.lisp

fix for osx
Update a.lisp

missing accessors for the vert-data, updated expected usage
Merge pull request #16 from jkordani/master

a change to get a.lisp example working again, and a change to get osx framed windows.
Modularizing according to packages.

Modularizing allows the community to easily handle the code and make
quick changes. It makes the cepl interface clean for external user. It
open up more options for easy management of code.

For example one could replace the maths package with a standard
one (sb-cga) in the future or separate out the maths package as an
entirely independent project.
Adding varjo as a submodule

This brings varjo as a part of the cepl source. The idea here is to
reduce the steps needed to start using cepl.It just makes sense to have
varjo and cepl together in the same project.

However to preserve varjo's status as a independent project we are
bringing it as a git submodule. Once the repository is cloned one has to
simply do a

$ git submodule update --init
Bringing varjo into the cepl system definition

This commit removes the dependency on varjo as an external system and
instead makes it internal to the cepl system.
Updating documentation to remove varjo requirement