[Lazarus] JSON - RTTI streaming.

[Michael Van Canneyt]

Hello,

For those of you that need JSON support:

I have committed support for streaming published properties 
(properties for which RTTI  is generated) from objects to 
JSON and vice versa, in a unit fpjsonrtti.

Not the full streaming as implemented in the classes system is supported:
- No DefineProperties.
- No methods.
Although it should not be difficult to add support for this.

In contrast, it can stream simple collections and stringlists 
(with ojects attached) in various ways.
There are various events to influence the streaming process.
This should be more than enough to stream objects to and from a web-browser.

I have committed an example and a testsuite.
All this is in packages/fcl-json.

Despite the fact that the testsuite runs OK , 
I'd like to ask those for whom it might be useful to test the 
code and report any errors you find to me. Suggestions for 
improvements are also welcome.

Michael.