Be sure the object's inventory serial is incorrect before dirtying the inventory

Thanks to Ubit for pointing this out
Sync LLAssetUploadResponders with upstream

Move LLSendTexLayerResponder into llviewertexlayer.cpp to reduce diff noise
Sync llviewerobjectbackup with Cool VL Viewer

Note to Translators:
-Adds translation work to floater_object_backup.xml
-Adds ImportFailed, ExportAborted, and ConfirmAbortBackup to notifications.xml

Turns LLViewerObjectBackup into an LLFloaterSingleton.. but eventually, this should probably be an instance tracker on the uuid of the object to export or something instead.
Solve Issue 1539: XML Export consistently fails as of latest alpha (build 5824)
Comment out something from the llviewerobjectbackup.cpp sync that looks iffy and seemed to cause malfunction.