[omniORB] Preliminary Python valuetype support

[Duncan Grisby]

I have checked in alpha support for valuetype in omniORBpy. To get it,
you must get the omni4_1_develop branch of omni and the
omnipy3_develop branch of omniORBpy.

Some notes:

 - It is not extensively tested yet, so I won't be surprised if you
   find bugs.

 - I have only tested it on Linux, so it may not work at all on other
   platforms. Other Unixes are likely to work; it is quite likely that
   it will not work on Windows yet.

 - I have not done any interoperability testing yet. If you have
   existing code using valuetypes, it would be helpful if you could
   try talking to it from omniORBpy.

 - Abstract interfaces are not yet supported.

 - Custom marshalling is not supported, and may never be. Anyone want
   it?

 - The rest of the valuetype specification is implemented, including
   chunking, truncation, supporting of interfaces, valueboxes and so
   on.

 - Values are always sent chunked, so any ORB that doesn't support
   chunking (TAO, I believe) will not be happy.

Please try it out and let me know how you get on. Please post any
feedback to the omniorb-dev list, rather than here.

To implement Python support, I've added facilities to the ORB core to
support chunking and other things to do with valuetype, so the
framework is there for implementing valuetypes in C++. If anyone would
like to volunteer to work on that, that would be great...

Cheers,

Duncan.

-- 
 -- Duncan Grisby         --
  -- duncan at grisby.org     --
   -- http://www.grisby.org --