OSL 1.10.7

Release 1.10.7 -- Oct 1, 2019 (compared to 1.10.6)

• Adjust for deprecated material in more recent Qt releases. #1043
• Fixes for MinGW compiler. #1047
• Texture "missingalpha" optional parameter generated incorrect code and
  crashed. #1044
• Fix incorrect optimizations surrounding 'exit()' calls in the middle
  of certain shader code blocks. #1051
• LLVM 9 / clang 9 compatibility. #1058
• Fixes to Travis CI system to keep up with OIIO master recently upgrading
  its minimum required CMake. #1065