New repo organization and build process.

v2.0 of Durandal is moving to a single file deploy model for the
library. durandal.js will deploy along other 3rd party libraries, rather
than within your SPA's application code. Plugins and transitions, by
default, will also deploy along side durandal.js with other 3rd party
plugins. However, this can easily be changed by removing or altering the
requirejs.config paths.

As part of this process, we are reorganizing the git repo to separate
out the library's source from distribution files, create a build process
and more clearly define the difference between the core library and the
various platform support options we have.

NOTE: The platform support as of this commit is broken.