[IronPython] DLLs directory in the default path

[Sanghyeon Seo]

This is a feature request.

CPython on Windows have DLLs directory, in addition to Lib directory,
in the default path. In my opinion, this is a good idea for IronPython
too.

One could throw MySql.Data.dll to that directory, for example. A
criteria for what to put into DLLs and what to put into Lib would be,
anything you would clr.AddReference goes to DLLs.

-- 
Seo Sanghyeon