#177370: synchronization problems with web.xml editor

Please review a fix for:
http://netbeans.org/bugzilla/show_bug.cgi?id=177370

Description:
2 synchronization problems related to web.xml editing
(see the description in the issue)

Impact:
Both data inserted in graphical editor or data inserted by the wizard 
may by lost for user

Fix: described in bug with much detail

Impact: not aware of any, rely also on QA and code reviewer to verify 
the fix.

Reviewers: Michal Mocnak, David Konecny.

Thanks