RDF 1.3.0

• Internal refactoring to the internal stream abstraction. It no longer exposes Seek() and Tell(). There's no change to user streams for now; but a future release will switch to a matching API or may expose a new user stream which doesn't expose Seek(), Tell(). If you're implementing a custom stream, you'll notice that every read and write operation will be preceded by a Seek() now.

  This also clarifies how stream wrapping works. Previously undocumented, but assumed, was that the stream was at position 0, and not modified outside. It was already a bug before if those conditions weren't true, but now it's actually documented.

• Fix bug in rdfm which would incorrectly write the last chunk's data when merging an empty chunk.

• Change validation for the rdfChunkFileReadChunk* read functions such that a nullptr for the buffer argument is valid if the requested size is 0. Previously, this would fail with an invalid argument error.

• Remove support for VCPKG again. Unfortunately, the upstream port file has never been finished, and the relatively intrusive support added in 1.2 caused more problems than it solved. If there's interest in re-adding VCPKG support, please open an issue or PR.