Adding Reference to Myra

There are two ways of referencing Myra in the project:

1. Through nuget: https://www.nuget.org/packages/myra (works only for MonoGame)

2. As source code(works for all supported platforms):

   a. Clone this repo.

   b. Add src/Myra/Myra.<platform>.csproj to the solution.

   • If FNA is used, then you would need to clone FontStashSharp too. And overall folder structure is expected to be following: