Create functions for saving and loading from a config file.
Move XDG_CONFIG_HOME stuff out of ask_for_preferred_install_dir to config file functions.
Fix more tabbing issues.
exit_with_error() should only output an error and quit, nothing more.
This should resolve https://github.com/andrewd18/df-lnp-installer/issues/30
Install all files to a DEST_DIR first, then copy.
Fix issue where an older config file might not leave us without defaults.
Only attempt to restore soundsense packs if they exist.
Remove unused functions. Clarify error case in copy_dest_dir_to_install_dir.
Fix some error messages and user output.
Cleanup folders after an install.
Fix issue with trailing / that borked cp.
Add mkdir command.
Fix a few minor directory detection issues.