New IDL proposed for TaskContext / corba transport

I finished the initial version of the new IDL files. Major changes are:

* All structs,interfaces,enums,... have the same name as in C++, except:
* Every struct, interface, enum,... is prefixed with 'C' to avoid name clashes
with pure C++ code
* Module RTT::Corba -> RTT::corba (as in C++).
* ControlTask -> CTaskContext
* TaskObject -> CServiceProvider
* CDataFlowInterface is as proposed by Sylvain Joyeux, with 'minor'
* Get operations/attributes/properties through CServiceProvider
* No more factory functions, just call the interface to get a prop/attribute
value or call/send a method. This will greatly relax memory requirements on
client and server side and improve ease of use as well.

The underlying idea is to reflect the C++ structure 1:1, but only from an
introspection view. Ie, you can ask/use what's there, but not add
functionality using this interface (for example, adding a port or property).

I've put doxygen generated pages here:

Which has been made from the rtt-2.0-mainline. I'll now start porting the
implementation to this IDL.