Revert "Renamed files containing project meta information: Fixed internal links."

This reverts commit 6a68256fb4077960106bc5d852bf8637723c808d.

Conflicts with Github.
Revert "Renamed files containing project meta information: used uppercase for file extension."

This reverts commit 34cde1b3f7e4447e637798af45247ab1cb619dbf.

Conflicts with Github.