ignore gp binary
ignore intellij files
correct read me. 'list' isn't a gopack-specific command. we use 'dependency tree' presently.
make necessity of dependency fetching explicit in the model rather than implicit in the return of a null dependency list
Merge pull request #47 from d2fn/dependencytree

Error generating dependency tree info when no fetching is needed.
baby steps - it puts the provider into the configuration
add the notion of a source and all the plumbing that comes with it; add error returns to some methods that were calling exit(1) from outside main.go making it hard to test