Add mvws_next/prev to sent window to relative workspace

Useful for multi-head configurations to send window to other-monitor.
Fix xscreensaver-command example.
Update Italian man page.
Man page fixes, mostly spacing related.
Reorder LDFLAGS in Linux Makefile to work with --as-needed.
Fix warp_pointer centering.

Pointer now centers on the following actions:
	swap window
	move/resize floated window
	stack reconfiguration
	cycle/flip layout
	maximize toggle

Fixes #71
Switch mouse buttons