character_map appends a random string to the end

[alanking]

Whenever the character_map event handler method is defined and it makes substitutions in a path, it also appends some random characters to the end of the resulting string, joined by an underscore.

For example: /data/ufs/tmpwv962nhj/test_character_mapped_top_level_file with a character_map which substitutes underscores (_) for hyphens (-) results in this logical path: /tempZone/home/rods/tmpwv962nhj/test-character-mapped-top-level-file-vuBRXjbeErHo6. Notice that the joining underscore was also substituted.

I believe this is here to prevent naming collisions in the event that multiple objects or collections are mapped to the same logical path. I could not find anything about this in the README, so we need to document this behavior and its justification.

Please be precise when documenting the behavior. It is very difficult to write tests for this behavior because I do not know how the random appendages are generated, so I cannot make assertions about expected logical paths.