OSL 1.10.4

Release 1.10.4 -- Apr 1, 2019 (compared to 1.10.3)

• LPEs: forbid LPE repetitions inside groups. #972
• Build process: build script finding of LLVM is now more robust to certain
  library configurations of llvm, particularly where everything is bundled
  in just one libLLVM without a separate libLLVMMCJIT. #976
• oslc: Improve warnings about ill-advised use of the comma operator. #978
• oslc: Fix an assertion/crash when passing initialization-lists as
  parameters to a function, where the function argument expected was as
  array. #983
• oslc: Fix an assertion/crash for certain type constructors of structs,
  where the struct name was not declared. (This is an incorrect shader,
  but of course should have issued an error, not crashed.) #988
• Note: The experimental OptiX path is not expected to work in this branch!
  Development has continued in the 'master' branch. If you are interested in
  testing the OptiX support while it's under development, please do so with
  the master branch, because fixes and improvements to the OptiX support
  are not being backported to the 1.10 branch.
• Tested and verified that everything builds and works correctly with
  Clang 8 and LLVM 8.0.