Fixes for filenames, string writing, -r on Ubuntu, requirements update

[john-corcoran]

Hi there, many thanks for making this script available! It was just what I needed.

Here are some changes I made to get things working on Windows 10 20H2 and Ubuntu 20.04 for an iPhone 4 backup:

1. writer.py: was trying to concatenate None objects with output strings, so wrapped all list objects in str() when concatenating.
2. manifestMbdbParser.py: my backup had some files with ':' in the filename which Windows wouldn't allow, so added a check on the filename before copying.
3. manifestMbdbParser.py: updated method to get domain_path and dest_path_root, which corrects file output location on Ubuntu when using -r.
4. requirements.txt: 'kaitaistruct' added, 'pathlib-revised' corrected.

Thanks again!
John