Added Megaco support courtesy of Gianluca Costa


git-svn-id: https://svn.ntop.org/svn/ntop/trunk/nDPI@7739 a02cd0c1-8e76-42e1-a119-56f9641475e2
Reworked configure


git-svn-id: https://svn.ntop.org/svn/ntop/trunk/nDPI@7740 a02cd0c1-8e76-42e1-a119-56f9641475e2