Word2007 : Support Multiple headers

Author: Progi1984

changelog.txt

@@ -30,6 +30,7 @@ Fixed in branch for release 0.7 :
 - Feature:  (Progi1984)       GH-2              - Implement ODT Writer
 - Feature:  (kaystrobach)                       - Word2007 : Add rowspan and colspan to cells
 - Feature:  (RLovelett)                         - Word2007 : Support for tab stops
+- Feature:  (RLovelett)                         - Word2007 : Support Multiple headers
 - General:  (MarkBaker)                         - Add superscript/subscript styling in Excel2007 Writer
 - General:  (deds)                              - add indentation support to paragraphs
 - General:  (Progi1984)       GH-27             - Support for Composer