Each DiveItem (which is a wrapper around diveId with some virtual
functions), had a member icon_names, which is an array of
four QStrings. These were not used anywhere and must be an obscure
oversight and was probably planned as a static cons array?.
In any case, remove it.
There *was* a function-local analogous icon_names array in
DiveItem::data() though. This array would initialize four
QStrings from C-string literals on every invocation. Make
this array static, local to the translation unit and use
the QStringLiteral macro to construct the QString object at
compile-time.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>