Require pointer lock when setmousepos is called repeatedly

[pdjstone]

Currently in setmousepos, a pointer lock is only requested if the mouse cursor isn't visible, or if the mouse and pointer aren't linked.

For now, if setmousepos is called when the cursor is visible and we're using absolute mouse positioning, then it's basically ignored since the absolute mouse position overrides the requested position. That generally doesn't cause problems when a program just wants to centre the pointer once.

However if a program is changing the mouse position repeatedly/continuously then we should switch to relative mouse mode.

Programs that currently cause issues:

• Heimdall (the drunken axe throwing)
• Pipe Mania (the mouse cursor in the options menu)
• Warfarin Module - Mouse Cursor Movement Reset archimedes-live#35