Fix OmniSharp --encoding switch to apply to both stdin and stdout
Fix OmniSharp --encoding switch to apply to both stdin and stdout

When the --encoding switch was specified, it unintentionally only applied to stdin. This was due to the fact that the `SharedConsoleWriter` was instantiated before `Console.OutputEncoding` was set. Because `SharedConsoleWriter` initializes itself with the current value of `Console.Out`, it had the default encoding rather than
the intended encoding.

DustinCampbell/omnisharp-roslyn,OmniSharp/omnisharp-roslyn,DustinCampbell/omnisharp-roslyn,OmniSharp/omnisharp-roslyn