Use repr() on exceptions, inform if using 'replace'.
Merge remote-tracking branch 'refs/remotes/ivan/feature/improve-unicode-logs' into develop
memory store for append/fetch/copy
move server to its own file
add enum dependency
split messageparts
move utilities
add soledadstore class
move parts-related bits to messageparts
pass soledad in initialization for memory messages
debug info
Unset new flag after successful write
flags use the memstore

* add new/dirty deferred dict to notify when written to disk
* fix eventual duplication after copy
* fix flag flickering on first retrieval.
use enums for dict keys
recent-flags use the memory store
handle last_uid property in memory store
fix find_charset rebase
docstring fixes