Make VSGI 1.0

[arteymix]

For the coming minor release (v0.4.0), it would be really great to make a stable release of VSGI so that other users could reuse this piece to write Web application in Vala.

There's a couple of changes I would like to introduce first:

• merge mock and CGI code into Request and Response so that these two just become concrete classes instead of abstract
• make it more friendly from an introspection perspective and have some PyGObject testcases
• add support for Windows (see Windows support #146) and Mac OS
• mark all APIs as stable and 1.0
• support multipart input and output streams

[arteymix]

I'm considering updating the whole middleware stack to be class-based, which would result in a very nice introspection for writting apps using Python or JavaScript.

By the way I merged the GObject Introspection support! Here's a sample app: https://github.com/valum-framework/valum/blob/master/examples/gi/app.py

[arteymix]

So far VSGI is well supported and will require some testing, Valum could be next, but it's not for the 1.0 schedule.