rework of LGAutoPkgTask

@futureimperfect , @jsenick 

I did a reworking of this to address some potential issues, especially #153 and #126  
        -- first pass at thread safety
	-- moved numerous items from ivars to properties
        -- overall more persistent properties  
	-- implemented proxy support
	-- tmp file cleaned up after autopkg run

If you guys have time, would you do a build and see if this successfully addresses either issue.
Keep me posted, 

And Josh, now there's a line that's logged on dealloc that has the full invocation of autopkg that starts
"Completed AutoPkg Task:" let me know what that is producing on the machine your having #153 issues with.

Thanks,
--Eldon