Add configuration for gulp/gulpfile location #84
Description
There seems to be an increasing need for complex project structures where gulp and/or gulpfile.js are not in the project root.
Example use case:
.
├── .git
├── foo
│ ├── gulpfile.js
│ └── node_modules
└── bar
The goal would be to add a guppy entry in package.json with a property that sets an override for the gulpfile.js location or override the project path in such a way that guppy executes in the correct directory for gulp.
Suggestions for better/best approaches for this are welcomed.