Merge pull request #17 from anchsm/master

Fixed from The Witness: emit non-deprecated texture lookups for >1.20, and add x64 MSVC config
tests: add test that exposes constant variable optimization bug
tests: improve test that exposes constant variable optimization bug
fix too eager constant variable optimization; now only mark them as const if there's one assignment outside any branches or loops
tests: safer
fix lower_jumps to report progress properly