Without this, repository paths or names containing e.g. & characters or html
tags yielded strange results, possibly allowing cross-site scripting attacks.
There were no RSS nor Atom feeds for the branches page. Different hgweb
templates linked to different feeds on their branches page (some linked to the
tags feed, some to the log feed and some to the unexisting branches feed).
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.
