Improve update-enet.sh to support local patches.  And update enet.
Add an option to force a particular listen port.

And clean up the TraversalClient lifecycle somewhat.
Fix for gratuitously incompatible Android.
Start refactoring IniFile:

- Don't do a linear search in Delete.

- Move less frequently used methods into Section rather than being
  inconsistent or duplicating.
Fix out-of-tree build on OS X.
Put a lock around writes to the FifoQueue.