* fix issue #940 - KeyError in get_dict_from_list
- cause of error : defaultdict added more defaultdict while attempting to traverse the tree, but once a 'potential leaf' node was added, it was added as a dict, not a defaultdict.
- two possible solutions:
- 1 - change everywhere that adds a 'potential' leaf node to add a defaultdict (ie nested_dict()) - this occurs in several places, but not many.
- 2 - change get_dict_from_list to add a default dict (not defaultdict) when traversing the tree, for the case where a multi-level node is added on top of an existing node. This requires only changing a single location, and means that the dictionaries returned by accessing the tree will behave like normal dict (ie, won't by default add missing keys).
* Add test case for issues #940 and #925
* add support for 'diff --json-lines' available in borg 1.1.16.
* fixes issue #901 (diff not handling CR/LF in filenames)
* improve `pretty_bytes()` formatting function
