LLVM trunk build fail fix (MDNode interface change)
Added some more functions to knc.h:
- __scatter64_i64
- __scatter_base_offsets32_double
- __scatter_base_offsets32_i64
Disable optimization to eliminate illegal results
- fixed 'cast_trunc', 'cast_zext' and 'cast_sext' implementations (the previous was faulty)
- added '__select (i8/16)', '__equal_i8/16_and_mask', '__not_equal_i8/16_and_mask' functions
Merge pull request #901 from ncos/ispc_build_fails

LLVM trunk build fail fix (MDNode interface change)
Merge pull request #902 from Vsevolod-Livinskij/knc_header_fix

Knc header fix
Merge pull request #904 from jbrodman/master

Disable optimization to eliminate illegal results
Merge branch 'master' of https://github.com/ncos/ispc into knc-backend-merge

Conflicts:
	examples/intrinsics/knc.h
removed unnecessary &255's (knc.h)
updated fail_db.txt to hide 9 new runfails and tests that have been fixed
Merge pull request #903 from ncos/knc-backend-merge

Add several functions to knc.h
fixed ISPC compilation fail caused by the change of llvm::Value to llvm::Constant in DIBuilder member functions (LLVM commit 222070)
Merge pull request #906 from ncos/ispc_build_fails

fixed ISPC compilation fail caused by LLVM DIBuilder API change
Tracking LLVM trunk: SmallPtrSet changes
Merge pull request #908 from dbabokin/trunk

Tracking LLVM trunk: SmallPtrSet changes
Fix for DWARF debug info generation pipeline

Applies to LLVM-3.4, -3.5 and -trunk builds of ISPC
Build fix for LLVM trunk - changed include structure
Merge pull request #910 from dbabokin/trunk

Build fix for LLVM trunk - changed include structure
Merge pull request #911 from aguskov/master

Fix for DWARF debug info generation pipeline
Fix for max/min_varying_uint/int64