Bump to version 7.6

doc/org.texi

@@ -4,8 +4,8 @@
 @setfilename ../../info/org
 @settitle The Org Manual
 
-@set VERSION 7.5
-@set DATE March 2011
+@set VERSION 7.6
+@set DATE juillet 2011
 
 @c Use proper quote and backtick for code sections in PDF output
 @c Cf. Texinfo manual 14.2