comctl32/listview: Setting item text to callback stub value already having it raises item-change notifications.

Use same new text comparison rules for both items and subitems.
Based on patch by Stefan Stranz.

comctl32/listview: Don't offset item box to item position on LVS_EX_FULLROWSELECT if item isn't in leftmost column.

winedos: Move VGA_SetGraphicMode() up a bit and make it static. VGA_GetModeInfoList() is unused so remove it.

dbghelp: Improve speed of our hashtable implementation by remembering the last element added to every bucket.