pgsql: Adjust plpython to convert \r\n and \r to \n in Python scripts,

Log Message:
-----------
Adjust plpython to convert \r\n and \r to \n in Python scripts,
per recent discussion concluding that this is the Right Thing. Add
regression test check for this behavior. Michael Fuhr

Modified Files:
--------------
pgsql/src/pl/plpython:
feature.expected (r1.9 -> r1.10)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpython/feature.expected.diff?r1=1.9&r2=1.10)
plpython.c (r1.58 -> r1.59)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpython/plpython.c.diff?r1=1.58&r2=1.59)
plpython_function.sql (r1.6 -> r1.7)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpython/plpython_function.sql.diff?r1=1.6&r2=1.7)
plpython_test.sql (r1.2 -> r1.3)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpython/plpython_test.sql.diff?r1=1.2&r2=1.3)