dbdc758c27cfdda9d255742b6c6ff4d1b7be82df doc: Improve doxygen readme navigation section (Jon Layton)
c15ac2c0aa45c59aee6d36c2d6d5210290dc601c doc: Move doxygen intro to file for USE_MDFILE_AS_MANPAGE (Jon Layton)
Pull request description:
With `USE_MDFILE_AS_MAINPAGE`, this moves the introductory Doxygen comment to its own file. This makes `bitcoind.cpp` cleaner.
It also removes the `\mainpage` header text, which was smaller than the section titles, and improves the Navigation section.
ACKs for top commit:
promag:
ACK dbdc758c27cfdda9d255742b6c6ff4d1b7be82df.
Tree-SHA512: 9352baad655877437913b74dc8888a71d1cccf55a837657ee2630fde3f427d0f0339155b7ab3d9e63a9edb9d53512d747eafcb11987a7c26c47a6df2eca93351
