- Add new queries: TProgram::getUniformTType and getUniformBlockTType,
  which return a const TType*, or nullptr on a bad index.  These are valid for
  any source language.

- Interface name for HLSL cbuffers is taken from the (only) available declaration name,
  whereas before it was always an empty string, which caused some troubles with reflection
  mapping them all to the same index slot.  This also makes it appear in the SPIR-V binary
  instead of an empty string.

- Print the binding as part of the reflection textual dump.

- TType::clone becomes const.  Needed to call it from a const method, and anyway it doesn't
  change the object it's called on.

- Because the TObjectReflection constructor is called with a TType *reference* (not pointer)
  so that it's guaranteed to pass in a type, and the "badReflection" value should use a nullptr
  there, that now has a dedicated static method to obtain the bad value.  It uses a private
  constructor, so external users can't create one with a nullptr type.