solving a small bug where ASP_UDP_USE_EXISTING_IP did not properly use LINK_NAME (it added an alias) caused a refactoring because common code in the pluginhelper was not common at all.  The algorithm for determining the alias (and whether to even do so) is very specific to UDP transport for example.  Common code is stuff that wraps complex Linux socket ioctls, etc.  Like getting IP address from an interface, etc.  Also fixed an issue where ASP_UDP_USE_EXISTING_IP was assigning the IP address to the interface.  This was happening on top of the same address already assigned so was essentially a no op.  But at the same time its a bug waiting to happen...
merge from github