Program crashes when navigating to 'c' drive in WSL

[darylwright]

To reproduce:

1. Start navigation in the mounted 'c' drive (i.e. the start directory when opening up a WSL terminal, /mnt/c/Users/<user>).
2. Keep navigating to parent directories until unable to. This happens when in the Users directory and navigating up.

Observations:

• In WSL, /mnt/c is inaccessible due to insufficient privileges.
• I realize I built ci to assume parent directories are all accessible. This is definitely not the case, especially when considering usage via non-root accounts in Linux.

Possible solutions:

• Detect if the parent directory is inaccessible, and prevent navigation in this case.
• Create quick links to well know directories, such as the starting directory, the home directory, and the root directory. These can include other directories in the future. This will prevent being stuck in a subset of directories as in this case.