Add option to specify Cake nuget source

[devlead]

I.e. if want to run from the MyGet nightly feed.

[gep13]

@devlead I had the same idea last night, and I came here to create this exact issue 👍

[gep13]

@devlead do you remember what the thought process here was again? It completely escapes me 😄

[frozenskys]

@gep13 @devlead - This sounds like the same issue I'm having (see below) - if it is I may have a fix that I could raise a PR for if you are interested?

We have an issue where our on premises TFS build machine is not allowed to access nuget.org but we do have an internal feed using Klondike. Unfortunately, this means using the cake-vso task doesn’t work, as it hard coded to nuget.org, both for fetching nuget.exe and for installing cake + tools from the package.config.

[gep13]

@frozenskys PR's are always welcomed 😄

[agc93]

Resolved by #30