Vulture exposed the following dead code:
- AppendLineParse was only used for reading the history text file, which is now
a sql database (and the import code for the old text file is simpler and does
not need a complex line parser)
- async_read_done is no longer used as importing the history text file is
synchronous (and should only happen once)
- config._init_key_config is unused as it was moved to keyconf.init
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