resolveCwd should check for meta.json and possibly .git

[andrewdeandrade]

While testing dependency fetching, the way I was testing exposed a subtle bug that occurs when there is a folder higher up in the cwd path called idl. I was trying to test in temp folder deep in my home folder, but because I had a folder called idl up at the root of my home directly, idl placed the fetched idl files there instead. Additional checks should be added to determine the correct idl folder to use. Checking for a child called meta.json should help here. Additionally checking for a sibling called .git should help as well since the idl/ folder is expected to be at the root of a repo (but I have seen at least one repo that didn't do this).

No one else has yet complained about this bug, so I'll noodle on a fix for it some more since the heuristics used to determine cwd aren't perfect.