include pexpect/bashrc.sh, remove old entries

closes issue #280, where using replwrap for bash
will likely result in error, because the dependent
--rcfile=bashrc.sh is not found when pexpect is
packaged.

MANIFEST.in

@@ -1,8 +1,7 @@
 recursive-include doc *
 prune doc/_build
 recursive-include examples *
-include README LICENSE INSTALL
-include setup.py pexpect.py fdpexpect.py pxssh.py screen.py ANSI.py FSM.py
-include test.env tools/testall.py
+include README.rst LICENSE
+include setup.py pexpect/bashrc.sh
 recursive-include tests *
 global-exclude __pycache__ *.pyc *~