KOTOR: Fix usage of dynamic_cast<>()

dynamic_cast<>() to a pointer may return 0, which has
to be checked for.
dynamic_cast<>() to a reference may throw an exception instead.

Coverity issue 1038265.
NWN: Fix format string type mismatch

Coverity issue 1038251.
NWN: Fix a leak in loadEquippedItems()

Coverity issue 1038250.
NWN: Fix possible leak in mainMenuLoop()

Coverity issue 1038249.
NWN: Initialize _itemNumber

Coverity issue 1038217.
GRAPHICS: Fix a leak in TXB::readHeader()

Coverity issue 1038248.
GRAPHICS: Fix potential invalid free in the copy constructor

Coverity issue 1038205.
GRAPHICS: Fix potential invalid free in the copy constructor

Coverity issue 1038204.
GRAPHICS: Make the ModelNode destructor virtual

Necessary, since we delete upcast ModelNode pointers.

Coverity issue 1038193.
COMMON: Catch exceptions thrown in printException()

Inception...

Coverity issue 1038238 and 1038240, again.
COMMON: Catch exceptions thrown in findGame()

Coverity issue 1038237.