Brainweaver: let edges connected to center node be bendable again

[richelbilderbeek]

162 is not exactly what the employer wanted: the arrows must

1) not have text on them 2) must have a handle to be able to bend the node

Suggested approach:

• Put a QtNode or ancestor classes at the midpoint
• Prevent this class to have text
• Disallow it to be edited

Additionally, bump up the version of Brainweaver (in pvdbmenu.cpp), add comment 'let edges connected to center node be bendable again' as this new version will be sent to the employer again.

[richelbilderbeek]

Done with 22300a7bb008ce700b98613ec265dab55f7f16f5