Include tmpl files in manifest template. Workaround for #2498.

Tests once again pass on an extract of the sdist.

MANIFEST.in

-recursive-include setuptools *.py *.exe *.xml
+recursive-include setuptools *.py *.exe *.xml *.tmpl
 recursive-include tests *.py
 recursive-include setuptools/tests *.html
 recursive-include docs *.py *.txt *.rst *.conf *.css *.css_t Makefile indexsidebar.html
 recursive-include setuptools/_vendor *.py *.txt
 recursive-include pkg_resources *.py *.txt
 recursive-include pkg_resources/tests/data *
+recursive-include tools *
+recursive-include changelog.d *
 include *.py
 include *.rst
 include MANIFEST.in