Fix bug with lines ending in continuation markers (\).

We were incorrectly considering them complete.

IPython/core/inputsplitter.py

@@ -388,6 +388,10 b' class InputSplitter(object):'
         # inconsistent code/source attributes.
         self.code, self._is_complete = None, None
 
+        # Honor termination lines properly
+        if source.rstrip().endswith('\\'):
+            return False
+
         self._update_indent(lines)
         try:
             self.code = self._compile(source)

IPython/core/tests/test_inputsplitter.py

@@ -247,6 +247,13 b' class InputSplitterTestCase(unittest.TestCase):'
         isp.push('')
         self.assertFalse(isp.push_accepts_more())
 
+    def test_continuation(self):
+        isp = self.isp
+        isp.push("import os, \\")
+        self.assertTrue(isp.push_accepts_more())
+        isp.push("sys")
+        self.assertFalse(isp.push_accepts_more())
+
     def test_syntax_error(self):
         isp = self.isp
         # Syntax errors immediately produce a 'ready' block, so the invalid