set Env.widening to do widening, and do some clean up for unused codes, before working on distributedly and on-demandly constructing the cipa summary in shared summary
Merge branch 'security' of github.com:xwangsd/Scuba into security
on-demand constructing cipa summary for S2 methods, not done, begin to make it sound
fix the existing bug of on-demanding constructing and also add a collecting method to collect read shared summary information