Add NetShade cask

Adds a cask for NetShade, an anonymous proxy management tool.
Add Mono Framework MRE (Runtime) Cask.
Add Mono Framework MDK (SDK) Cask.
Merge pull request #1241 from gillesfabio/add-mono-mre-cask

Add Mono Framework MRE (Runtime) Cask.
Merge pull request #1242 from gillesfabio/add-mono-mdk-cask

Add Mono Framework MDK (SDK) Cask.
Add Xamarin Studio (MonoDevelop) Cask.
Merge pull request #1243 from passelin/netshade

Add NetShade cask
Merge pull request #1244 from gillesfabio/add-xamarin-studio-cask

Add Xamarin Studio (MonoDevelop) Cask.