Wake On Access (woa) - 'Just in time' WOL when accessing MySQL or FileShare Server

Forum thread : http://forum.xbmc.org/showthread.php?tid=124340

Replacement for abandoned pull request https://github.com/xbmc/xbmc/pull/1112 

Refactored solution based on work by @pieh including simple GUI-setup as discussed in old PR.

Working for Windows (tested by @kricker) and Linux (tested by @bilbonvidia) - but needs verification for other platforms.