Updated README.txt to README.md (#1375)

* 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

README.md

@@ -0,0 +1,85 @@
+HDF5 version 1.13.1-1 currently under development
+
+![HDF5 Logo](doxygen/img/HDF5.png)
+
+*Please refer to the release_docs/INSTALL file for installation instructions.*
+
+THE HDF GROUP
+---------------
+
+The HDF Group is the developer of HDF5®, a high-performance software library and
+data format that has been adopted across multiple industries and has become a
+de facto standard in scientific and research communities.
+
+More information about The HDF Group, the HDF5 Community and the HDF5 software
+project, tools and services can be found at the Group's website.
+    
+   https://www.hdfgroup.org/
+
+
+DOCUMENTATION
+-------------
+This release is fully functional for the API described in the documentation.
+    
+   https://portal.hdfgroup.org/display/HDF5/The+HDF5+API
+
+Full Documentation and Programming Resources for this release can be found at
+
+   https://portal.hdfgroup.org/display/HDF5
+
+See the RELEASE.txt file in the release_docs/ directory for information specific
+to the features and updates included in this release of the library.
+
+Several more files are located within the release_docs/ directory with specific
+details for several common platforms and configurations.
+
+    INSTALL - Start Here. General instructions for compiling and installing the library
+    INSTALL_CMAKE  - instructions for building with CMake (Kitware.com)
+    INSTALL_parallel - instructions for building and configuring Parallel HDF5
+    INSTALL_Windows and INSTALL_Cygwin - MS Windows installations.
+
+
+
+HELP AND SUPPORT
+----------------
+Information regarding Help Desk and Support services is available at
+
+   https://portal.hdfgroup.org/display/support/The+HDF+Help+Desk
+
+
+
+FORUM and NEWS
+--------------
+The following public forums are provided for public announcements and discussions
+of interest to the general HDF5 Community.
+
+   - Homepage of the Forum
+   https://forum.hdfgroup.org
+
+   - News and Announcement
+   https://forum.hdfgroup.org/c/news-and-announcements-from-the-hdf-group
+
+   - HDF5 and HDF4 Topics
+   https://forum.hdfgroup.org/c/hdf5
+
+These forums are provided as an open and public service for searching and reading.
+Posting requires completing a simple registration and allows one to join in the
+conversation.  Please read the following instructions pertaining to the Forum's
+use and configuration
+    https://forum.hdfgroup.org/t/quickstart-guide-welcome-to-the-new-hdf-forum
+
+
+SNAPSHOTS, PREVIOUS RELEASES AND SOURCE CODE
+--------------------------------------------
+Periodically development code snapshots are provided at the following URL:
+    
+   https://gamma.hdfgroup.org/ftp/pub/outgoing/hdf5/snapshots/
+
+Source packages for current and previous releases are located at:
+    
+   https://portal.hdfgroup.org/display/support/Downloads
+
+Development code is available at our Github location:
+    
+   https://github.com/HDFGroup/hdf5.git
+