1.12.0 Release

Notable Changes:

• Change code generation to reduce the stack usage in non optimized builds (Issue #1034)
  • Move required field support for oneof into a generated helper (#1041)
  • Work around stack usage for non optimize build and switch statements (#1040)
  • Work around excessive stack space in non optimized builds during oneof isInitialized (#1042)
• Revise the way storage calculations are done to take into account the cost of singular message fields since those directly increase the size of the containing message (#1046)
• Fix JSON coding/decoding of NullValue WKT (#1051)

Minor Changes:

• Minor oneof tweak: don't generate case nil when also generating a default (#1035)
• Factor out the common decodeJSON from all the wrappers (#1062)