(svn r8697) [cpp_gui] -Codechange: changed IsWindowOfPrototype() is a Window method

(svn r8696) [cpp_gui] -Codechange: changed GetMenuItemIndex() and ResizeWindow() into Window methods

(svn r8695) [cpp_gui] -Codechange: changed AssignWidgetToWindow() and InvalidateWidget() into Window methods

(svn r8693) [cpp_gui] -Fix: g++ compilation errors 'non-local function A uses local type B' (template arguments must have external linkage while local type has no linkage)

(svn r8683) [cpp_gui] -Codechange: first steps towards OO GUI (together with Bjarni) without changes in the logic
-Windows are now constructed/destroyed when needed instead of reusing them from _windows[25]. This array is now replaced by std::list<> of smart pointers (eliminates the need of _z_windows)
-some Window related functions turned into Window (or WindowList) methods
-note that although the number of windows is now unlimited, the maximum number of viewports is still hardcoded. This causes game crash when too many industry windows are opened.
-tested only on VC8/WinXP

(svn r8682) [cpp_gui] -Branch: branch for making the windows code object oriented
This will clean up a lot of hacks and remove some limitations.
It will also make it easier to understand how to create and handle the window interface.

(svn r8681) -Fix (FS#608): wrong comment (rfalke)

(svn r8680) [Configure] -Codechange: allow a bit more flexible code in check_compiler

(svn r8679) [Configure] -Fix: 'checking for' and 'checking' was used mixed, now only 'checking' is used
-Fix: 'checking host g++/gcc' is silly, changed it to 'checking host c++/cc'

(svn r8678) [PSP] -Add: added LIBS and CFLAGS needed to compile PSP
-Fix: PSP needs to link with gcc, not with g++ (don't ask)
-Fix: PSP doens't support threads