Add basic joystick support on Windows and Linux, with an option to compile it out.  winmm added to all .dsp/.vcproj/.dev projects.  Example 04.Movement updated to demonstrate the functionality.  Tested with 1 USB joypad on WinXP and Ubuntu 8.04 (via VmWare).

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@1687 dfc29bdd-3216-0410-991c-e03cc46cb475