* On init, rebuild the dictionnary only once
* Fixed first dictionary update to avoid rebuilding multiple times. Commented some very verbose debug logs (should create a new level: UVERBOSE or UTRACE)
* bump version 0.23: added parameters "Mem/LoadVisualLocalFeaturesOnInit", "Mem/FlannIndexSaved", "Kp/SerializeWithChecksum".
* Renamed Mem/FlannIndexSaved to Kp/FlannIndexSaved. Update UI Preferences with new parameters.
* commented some very verbose debug logs
* Warn flann index serialization not implemented on windows
* Warn flann index deserialization not implemented on windows
* Removing some verbose logs
* missing header (win32)
* Added GlobalMap::fullUpdateNeeded() function
* Adding log
* Save flann index even if links changed
* log time to serialize flann index
* Make dictionary modified only after we update
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Co-authored-by: Mathieu Labbe <mathieu@robust.ai>
