Reduce repository size

[mshavliuk]

At it's current state, installation of the ZI takes a lot of network bandwidth and thus a lot of time to download. Below are my suggestions to fix this problem and clean up the repository, making it easier to navigate around for the new users.

• Remove entire documentation directory (-40Mb)
  My suggestion is to remove the entire directory and focus on more conventional ways of maintaining the documentation, such as writing README.md and wiki pages.
  Using latex documents requires installing and learning how to use another complex tool to simply read the documentation. Moreover, the process of compiling the documentation requires the documentation on its own.
  Also, this directory includes fonts. They take 40mb of space during project installation (with my internet speed it adds an additional minute of downloading) and also have distinct license (OFL-1.1 license) which is not mentioned anywhere

• Extract the demo projects into another repository (-111Mb)
  The set of example projects deserve its own documentation, which would include the explanation of the data sources, the use cases, screenshots etc. At the moment, the /data directory which contains only the demo project and some screenshots adds 111mb to the repository size, (out of 256mb)