Implement continuous integration

As a first step for continuous integration I implemented some build
scripts based on fake, which should be executed on appveyor.

The build does the following:
 - Install dependencies for the build with paket
 - Install nuget dependenices of the Solution
 - Get the version with GitVersion and path AssemblyInfo
 - Build
 - Pack nuget package
Merge pull request #22 from yannisgu/ci

Implement continous integration