Some python 2.7 (and 3.3) compatibility improvements.

jedi/parser/grammar2.7.txt

@@ -57,7 +57,7 @@ break_stmt: 'break'
 continue_stmt: 'continue'
 return_stmt: 'return' [testlist]
 yield_stmt: yield_expr
-raise_stmt: 'raise' [test ['from' test | ',' test [',' test]]]
+raise_stmt: 'raise' [test [',' test [',' test]]]
 import_stmt: import_name | import_from
 import_name: 'import' dotted_as_names
 # note below: the ('.' | '...') is necessary because '...' is tokenized as ELLIPSIS
@@ -68,7 +68,7 @@ dotted_as_name: dotted_name ['as' NAME]
 import_as_names: import_as_name (',' import_as_name)* [',']
 dotted_as_names: dotted_as_name (',' dotted_as_name)*
 dotted_name: NAME ('.' NAME)*
-global_stmt: ('global' | 'nonlocal') NAME (',' NAME)*
+global_stmt: 'global' NAME (',' NAME)*
 exec_stmt: 'exec' expr ['in' test [',' test]]
 assert_stmt: 'assert' test [',' test]