added LLVM_3_6 var
fixed 3.6 llvm build in type.cpp
removed duplicatees in Makefile
checked Makefile 'if' constructions, fixed ReleaseNotes.txt, added comments to util.m4
rewritten comment for util.m4
Merge pull request #828 from ncos/ispc_build_fails

Add support for LLVM 3.6 build
update fail_db for 3.6
removed 'llvm/Config/config.h' from cbackend.cpp build for LLVM 3.5+
Merge pull request #829 from ncos/knc_faildb

update fail_db for 3.6
Merge pull request #830 from ncos/ispc_build_fails

removed 'llvm/Config/config.h' from cbackend.cpp build for LLVM 3.5+
merge with master
add '--quick-fix' option