Fix subtle bug with error message on Python 2.6 - code to be compiled must end in a newline.

closes gh-409
closes gh-424
closes gh-427
closes gh-431

IPython/core/interactiveshell.py

@@ -2130,7 +2130,7 class InteractiveShell(Configurable, Magic):
             prefilter_failed = False
             if len(cell.splitlines()) == 1:
                 try:
-                    cell = self.prefilter_manager.prefilter_lines(cell)
+                    cell = self.prefilter_manager.prefilter_line(cell)
                 except AliasError as e:
                     error(e)
                     prefilter_failed=True

IPython/lib/tests/test_irunner.py

@@ -105,10 +105,10 In [7]: autocall 0
 Automatic calling is: OFF
 
 In [8]: cos pi
-   File "<ipython-input-8-586f1104ea44>", line 1
+   File "<ipython-input-8-6bd7313dd9a9>", line 1
      cos pi
           ^
-SyntaxError: unexpected EOF while parsing
+SyntaxError: invalid syntax
 
 
 In [9]: cos(pi)