Build image.c as an extension; Fixed Windows support

[ptytb]

I've been having installing and functioning issues on Windows, now it seem to work fine.

I tried to do some things more cross-platform way.

I'm running rainbowstream on ConEmu terminal for Windows and commands do work, images are rendering.

Update: I've just tested it on Debian Jessie, it compiles and works.

[orakaro]

Gonna give this a test in next version release. Thanks for your effort!

[dogancelik]

It installs without any error, thank you @ptytb

# pip install git+https://github.com/ptytb/rainbowstream.git
Collecting git+https://github.com/ptytb/rainbowstream.git
…
Requirement already satisfied: python-dateutil 
Requirement already satisfied: arrow 
Requirement already satisfied: requests==2.5.3 
Requirement already satisfied: pyfiglet 
Requirement already satisfied: twitter 
Requirement already satisfied: Pillow 
Requirement already satisfied: PySocks 
Requirement already satisfied: pocket 
Collecting pyreadline (from rainbowstream==1.3.7)
…
Successfully built rainbowstream pyreadline
Installing collected packages: pyreadline, rainbowstream
  Found existing installation: rainbowstream 1.4.0
    Uninstalling rainbowstream-1.4.0:
      Successfully uninstalled rainbowstream-1.4.0
Successfully installed pyreadline-2.1 rainbowstream-1.3.7

Then I start:

# rainbowstream
RainbowStream latest version is 1.4.0 while your current version is 1.3.7
You should upgrade with pip install -U rainbowstream

Need tips ? Type "h" and hit Enter key!
[@dogancelik]:
We have connection problem with twitter stream API right now :(
☺☻[@dogancelik]: ☺☻

But I get a connection problem after starting rainbowstream, maybe it will be fixed after I upgrade to version 1.4.0.

Can you merge this? @orakaro