Add Sparkle Update framework to Mac OS Client for BOINC client updates

[lee.mccartney@…]

Please consider using the sparkle application update framework to the BOINC Mac OS client - its a free to use framework that seamlessly notifies users (and installs) program updates. General/Developer? info can be found at the website: ​http://sparkle.andymatuschak.org/

I realised that the BOINC version I was running was quite old, I am sure that other Mac OS users are also unaware that they may be running an older version, this could be prevented fairly easily with some modifications to the client software.