bump LLVM version
Apply UB constraints only on the relevant Phi branches

This patch fixes the unsoundness issue #13.
Add souper-check tool

This tool is based on souperweb-backend.cpp, but it's
intended to be run from the command line.
Skip phis with one operand (issue #61)
bump Klee version

bump LLVM version

bump Hiredis version

install the hiredis static library and include files by hand

don't try to use the hiredis dynamic library