Added @ prefix to PropertyName if it is a keyword or digit
Added @ prefix to PropertyName if it is a keyword or digit

Based on what I saw PetaPoco doing to fix property names that were C#
keywords. I changed the cleanup logic to add an @ symbol to the property
name so that it could be left untouched and compile correctly without
having to change the name in any way.

justshrey/Dapper.FastCRUD,MoonStorm/Dapper.FastCRUD,tenbaset/Dapper.FastCRUD