Loading time optimization (#1569)

* 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

---------

Co-authored-by: Mathieu Labbe <[email protected]>

corelib/src/Optimizer.cpp

@@ -608,8 +608,8 @@ void Optimizer::computeBACorrespondences(
 					}
 				}
 
-				if(sFrom.getWords().size() &&
-					sTo.getWords().size() &&
+				if(sFrom.getWordsKpts().size() &&
+					sTo.getWordsKpts().size() &&
 					sFrom.getWords3().size())
 				{
 					if(!rematchFeatures)