Detect parent directories rather than adding all child directories

[whitfin]

This is an issue related to node_modules, although other dependencies may have the same issue. Basically, there's a lot of noise in the entries list unnecessarily.

An example is a directory with this structure:

root/
  node_modules/
    moduleA/
      node_modules/
        moduleD/
          package.json
      package.json
    moduleB/
      node_modules/
        moduleE/
          package.json
      package.json
    moduleC/ 
      package.json
  package.json

This will add the following directories to your exclusions:

./root/node_modules/moduleA/node_modules
./root/node_modules/moduleB/node_modules
./root/node_modules

Obviously this is redundant as the final entry already covers the former. In a single project directory, my node_modules caused ~50 entries to be added, rather than a single entry. This is a pain when it comes to reversing the process, or just inspecting the excluded entries list.

[whitfin]

Actually, forget this - it was caused by a bad directory where I had node_modules in a non-node project, so there was no package.json!