when extensions are present to a sequence,

when extensions are present to a sequence,
for the individualk bits in the bitmap field for whether each extension
is present or not, add "(<extension name> [is|is NOT] present)" to the
tree item.

this makes the dissection of the extension bitmap more meaningful

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@7988 f5534014-38df-0310-8fa8-9805f1628bb7