initial commit for the console logger

This is a very basic implementation and is missing scoping altogether. Just wanted to put this out there for some feedback. The colors and format match the NLog configuration in the sample app, as evidenced by the image below. 
![consoleloggerinitial](https://cloud.githubusercontent.com/assets/2818455/4500693/3b65c814-4a98-11e4-998b-414ec6c792f6.png)

Should this also have `net45` support?

The other projects support it as well:
* https://github.com/aspnet/Logging/blob/dev/src/Microsoft.Framework.Logging/project.json
* https://github.com/aspnet/Logging/blob/dev/src/Microsoft.Framework.Logging.Interfaces/project.json

This would enable the console logger to work in non-ASP.NET 5 scenarios, such as EF7 on plain desktop .NET.