Update DustMite

Commits:
* 4b953aa Fix list-splitting post-processor
* 9a6e3ce --dump and --trace now use unique entity IDs
* aa32805 Add --trace debugging option
* f18950b Fix reducing individual files
* b2c8c31 Don't concat pointlessly
* fa5d982 Create disk cache directory if it doesn't exist
* 776eb9a Fix calculating sibling directory paths for . and ..
* 24ebc57 Add Concat reduction type (concatenate all data into a single file)
* 274c0a2 Fix checkDescendants