DefaultSupportedMessagesUltraVNC() and DefaultSupportedMessagesTightVNC() are never called

[badda71]

In file rfbproto.c, function InitialiseRFBConnection() libvncserver checks the RFB version sent by the server and calls DefaultSupportedMessagesUltraVNC() or DefaultSupportedMessagesTightVNC() depending on the received RFB version (3.4, 3.6, 3.14 or 3.16 for UltraVNC, 3.5 for TightVNC). However, the recent versions of the servers all report RFB version 3.8, so the server-specific capabilities are never set. This means, for example, that server-side scaling does not work anymore (because the capability is set in DefaultSupportedMessagesUltraVNC).
We need a new way of identifiying the servers - unsing the RFB version does not work anymore ...

[badda71]

Added pull request #506 to fix this issue.
With this, UltraVNC and TightVNC servers are not recognized by the RFB version, but by their specific security types (rfbUltra and rfbTight).