Do not set dirty flag on just loaded attributes, and due to this do not clear dirty flags after each load https://github.com/HarpyWar/pvpgn/issues/85 https://github.com/HarpyWar/pvpgn/issues/99

It saves the same functionality, but now it fixes bug when loading a next sql table into a memory (not we load a whole table on demand) - it clear dirty flags on previous modified attributes that were not saved yet.