* H5Lexists docs: Removed reference to 1.8.16 since the change is the 1.8.x releases, HDFFV-11289
* H5Oget_info_by_name, name can be any object, not just a group
* Converted README.txt to README.md and updated files referring to README.txt to README.md.
* removed references to README.txt
* updated MANIFEST
