Consider climbing the file system hierarchy looking for `.cogs/`

[jamesaoverton]

When running a Python script in subdirectories of a project, I was forced to use os.chdir("..") so that calls to cogs.foo() would be able to find the .cogs/ directory.

I think we should follow git's behaviour: if the .cogs/ directory can't be found in the current directory, climb the file system hierarchy to look for it. It would be good to take a minute to research git's actual behaviour.