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+
wiped out all LLVM 3.1 support
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+
reversed macros LLVM_3_6 to LLVM_3_5+ in .cpp and .h files
updated Makefile for reverce LLVM_3_6 flag
fixed broken Makefile (failed to build 3.5)
removed LLVM 3.1 option from python scripts
Merge branch 'master' of https://github.com/ncos/ispc into remove-support-for-old-llvm
remover LLVM 3_1 from cbackend.cpp
Merge pull request #831 from ncos/remove-support-for-old-llvm

Remove support for llvm 3.1
changed 3.5 repo path from tag to branch until rc2 is out
tail the run_tests.log (100 lines)