Build cache invalidation

[FeodorFitsner]

Syntax for specifying cache item dependencies:

folder_or_file -> dependency1,dependency2,...

For example:

packages -> **\packages.config
%APPDATA%\npm-cache -> package.json,bower.json

What if we could have some "dependencies" management for cache items by analogy with ASP.NET Cache? So you can tell AV, invalidate packages folder if <this>\packages.config changed.

The same could work for node.js (package.json) or ruby bundler (Gemfile).

*Request came from Ricardo Polo

[tkelman]

I totally missed you introducing the build cache feature. Gotta say, it's very well-executed and useful for files I was downloading on every build but never changing.

Some way of cache management / resets through the UI would be a nice future enhancement, but it already works pretty well as-is.