[Mono-osx] [MonoMac] patch for MM-addin, Existing Framework

[Miguel de Icaza]

Hello Duane,

> This patch enables "Add Existing Framework".

I am not familiar with MonoDevelop's engine, but the Directory. calls
look like they come from System.IO, and a lot of the IO that is taking
place here needs to be protected for IO errors.

Additionally, I am thinking that for regular builds it might be
faster/better to symlink the frameworks into the resulting .app
instead of copying the frameworks.   So perhaps we need to symlink in
this case and let the packager do the actual copying instead.

Miguel