Handle codebases with too many directories.
Handle codebases with too many directories.

- The number of directories is limited by the kernel parameter
  user.max_inotify_watches.
- For codebases that exceed the limit, error out immediately,
  and give the user an example sysctl command to raise the limit.

ahamilton/vigil,ahamilton/vigil,ahamilton/vigil,ahamilton/vigil,ahamilton/vigil,ahamilton/vigil,ahamilton/vigil,ahamilton/vigil,ahamilton/vigil