* ReviewParserOptions.cs: Encapsulates the command line options
  supported by the ReviewParser.

* Program.cs: Now using the CommandLineParser package to process the
  arguments.
Added the ability to parse a list of Apps that are either supplied via
  a json file, or retrieved from the database.

* ReviewsWorker.csproj: Added references to two new packages:
  CommandLine and log4net.
Updated the reference of Newtonsoft.Json.

* packages.config: Added the packages CommandLineParser and log4net.