Significantly simplify some code, and removes a lot of hacks.
Now, the proper way to get packages is from an HTTP repository.
The mkrepo.py uses the content of the old catalog.json to populate
a dds repository. This is also used in the test cases to spawn
repositories as test fixtures.
This is a very rudimentary version. All it does is copy and rename the
template header file and place it in the build directory in a special
subdirectory that is added as an #include-path.
There is some code duplication and cleanup necessary. There are a
few "magic strings" and "magic paths" that need to be removed as well.