declare missing dependencies

[kalikaneko]

the following dependencies are needed by pixelated but not declared in setup.py:

• chardet
• whoosh

[deniscostadsc]

Hi @kalikaneko

I did some experiments, that can be seen here.

I thought it could be a good ideia to parse requirements file, because we like to change a lot requirements file. It worked to get the packages, but it cannot install from the github repository, is installing from Pypi. I was looking at 'dependency_links' field on the setup to fix that but the first approach didn't worked. We'll have a look on it soon.

[kalikaneko]

parsing the requirements file, in my experience (and according to some previous people in pixelated too) is not a good idea. when you introduce pinning in the requirements file, you are injecting the pinning to the setup.py and therefore complicating the life of the maintainer for whatever platform that wants to distribute the package.

this was recommended by some people in the pixelated team in the past:
https://caremad.io/posts/2013/07/setup-vs-requirement/