This allows us to %include map-cmdline.<style> file in our .hgrc files. The
syntax is slightly different as hgrc doesn't support loading an external
template file, but map-cmdline files don't use this feature, so the syntax
can be considered identical in practice.
Unnamed section is remapped for backward compatibility.
Remove the `install_package_data' subclass of `install_data' and use
the `package_data' functionality provided by distutils instead. As
package data must be located within the package directory, the data
files are now generated in the build directory.
To simplify the functionality of this change, the top-level `doc' and
`templates' directories have been moved into the `mercurial' package
directory.
