Windows support
Merge pull request #655 from ifilippov/windows

Windows support in alloy
changed back to #define ISPC_FORCE_ALIGNED_MEMORY aligned_ld/st #else unaligned ld/st #endif. However load<64>/store<64> will still be unaliged w/o this define because of fails related to the issue #632
Merge branch 'master' into knc-fix
Merge pull request #656 from egaburov/knc-fix

restored ISPC_FORCE_ALIGNED_MEMORY
Examples makefiles to support setting single target via ISPC_IA_TARGETS
perf.py - target switch was added
avx1-i32x4 implementation as sse4-i32x4 with avx target-feature flag
target-[sse4|avx]_common.ll are twin brothers, which diffes only cosmetically. This commit makes them diffable. No real changes, except adding alwaysinline to sse version iof __max_uniform_int32/__max_uniform_uint32
Ordering functions in target-[avx|sse2].ll to be in the same order. No real changes, except adding a few alwaysinline in SSE4 target
Reasoning to use sse4 bitcode file
Make perf.py changes work as part of alloy.py
minor improvements in examples/common.mk
Fix bug with fail when --target=avx1.1-i32x8,avx2-i32x8 - avx11 is not a valid target anymore, need more complete string
Rebuild *.ispc when necessary
Add avx1-i32x4 to the list of supported targets
Adding avx1-i32x4 to alloy.py testing
Merge pull request #657 from dbabokin/avx-i32x4

avx1-i32x4 target
fail_db.txt update on Linux
Merge pull request #658 from dbabokin/fail_db

fail_db.txt update on Linux