Added warnings for data_files, setup_requires and dependency_links

docs/keywords.txt

@@ -86,6 +86,11 @@ associated ``setuptools`` feature.
     subclasses.
 
 ``data_files``
+
+    .. warning::
+        ``data_files`` is deprecated. It does not work with wheels, so it
+        should be avoided.
+
     A list of strings specifying the data files to install.
 
 ``package_dir``
@@ -144,6 +149,10 @@ associated ``setuptools`` feature.
     the Python version, used to specify the Requires-Python defined in PEP 345.
 
 ``setup_requires``
+
+    .. warning::
+        Using ``setup_requires`` is discouraged in favour for `PEP-518`_
+
     A string or list of strings specifying what other distributions need to
     be present in order for the *setup script* to run.  ``setuptools`` will
     attempt to obtain these (even going so far as to download them using
@@ -159,7 +168,13 @@ associated ``setuptools`` feature.
     when the setup script is run, you should add them to ``install_requires``
     **and** ``setup_requires``.)
 
+.. _PEP-518: http://www.python.org/dev/peps/pep-0518/
+
 ``dependency_links``
+
+    .. warning::
+        ``dependency_links`` is deprecated. It is not supported anymore by pip.
+
     A list of strings naming URLs to be searched when satisfying dependencies.
     These links will be used if needed to install packages specified by
     ``setup_requires`` or ``tests_require``.  They will also be written into