Building a library outside of Origin should simply require the programmer to
include the Origin.cmake module. This can be canonically done by testing for
an ORIGIN_ROOT environment variable and pointing the library at that.

The Core and Std libraries do not require the ORIGIN_ROOT variable to be
defined since they are in the Origin source tree. They simply rely on the
CMAKE_SOURCE_DIR variable to point to the top-level source directory and treat
this as the the root.

== TODO ==
Lots and lots of stuff to do for the build

1. A better documentation chain, possibly with a custom version of Doxygen