Added NuGet package Octokit 0.5.2
Added app-config.json file in DownloadGitHubRepositories.ConsoleClient project
Created abstraction over writing on console
Created IGitHubRepositoriesDownloader and empty implementation
Implemented Main() method of DownloadGitHubRepositories.ConsoleClient (suing IGitHubRepositoriesDownloader)
Implemented GitHubRepositoriesDownloader