10.7 and binary application support 

Be more cautious about interior pointers under GC
FSCopyObjectSync() seems to be problematic on Lion, use NSFileManage...
Changed SDKROOT to MacOSX10.6
https://github.com/sinbad/Sparkle/commit/66d3e181011e4183f1396aa41ea...
Adds support for relaunching binary applications with existing argum...
Changed SDK to 10.6