Use vim.bindeval() to avoid Unicode problems

Fixes #690.

pythonx/UltiSnips/_vim.py

@@ -124,6 +124,14 @@ def eval(text):
     return rv
 
 
+def bindeval(text):
+    """Wraps vim.bindeval."""
+    rv = vim.bindeval(as_vimencoding(text))
+    if not isinstance(rv, (dict, list)):
+        return as_unicode(rv)
+    return rv
+
+
 def feedkeys(keys, mode='n'):
     """Wrapper around vim's feedkeys function.
 
@@ -242,7 +250,7 @@ def _unmap_select_mode_mapping():
                     '| redir END')
 
             # Check if any mappings where found
-            all_maps = list(filter(len, eval(r"_tmp_smaps").splitlines()))
+            all_maps = list(filter(len, bindeval(r"_tmp_smaps").splitlines()))
             if len(all_maps) == 1 and all_maps[0][0] not in ' sv':
                 # "No maps found". String could be localized. Hopefully
                 # it doesn't start with any of these letters in any