Add Wake-on-LAN support for VNSI

As discussed in this Trac issue (http://trac.xbmc.org/ticket/15013) I've added support to VNSI for waking up the VDR server using WakeOnLan.

Additionally, I fixed a small typo regarding IconPath causing the hostname to be reset incorrectly.

This works for me and for end-users simply requires adjusting the settings.xml file with the MAC address. Then once XBMC starts the VDR server also goes up (running at 26 Watts so this guy is mostly off unless watching/recording).

My "concerns":
1) I added the WOL code fully in client.cpp - this should maybe go into VNSIData.cpp?
2) Naming convention should be changed?
3) No UI support as of now - based on my trac issue this seems to be a "not that important" feature, so allowing this feature only via XML file seems an option. If no UI, I still think we should have the language label set up none the less to have it "in place" already - or should I leave it away fully in the xml file?
Had to remove the "= NULL" as otherwise the two methods are ambiguous - as this is only called in one specific spot till date that should be fine I think.