Initial refractor for customisable icon window.
Refractor for customisable icon window: Item and help string reasdy
Added keypress action. All others mostly cconfigurable now - sit/stand left to do.
Added ranging windo icon help.  Trap NULL strings in get_named_string().
Added get_winid() and added console and map windows to view_window().
Decoupled sit/stand action and icon.
Removed unused combat_mode variable.
Added minimap to named windows (available to icon window).  Added null pointer protection for window lookup..
Renamed icon_window.c to icon_window.cpp
Rewrote icon window code using C++; making configuration simpler and cleaning up.
Updated make files to use icon_window.cpp
Leave the decision to free the icons to the icon_window code - just specify which mode we want here.
Icons are now freed automatically.
Example icon window xml files.
Fully working with run-time icon definition from xml files.
Simplifed interface for creating/switching icons.
Silently ignore missing xml files.