master: readme.md: Fix broken links an otherwise bring up to date.

readme.md

@@ -1,30 +1,21 @@
 # CppAD: A Package for Differentiation of C++ Algorithms
 
 ## Documentation
-[users guide](https://cppad.readthedocs.io/en/latest/user_guide.html)
+[users guide](https://cppad.readthedocs.io/latest/user_guide.html)
 
 ## License
 SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-or-later
 
 ## Install
 
 - The preferred method to test and
-  [install](https://cppad.readthedocs.io/en/latest/Install.html)
+  [install](https://cppad.readthedocs.io/latest/Install.html)
   CppAD uses [cmake](https://cmake.org).
 
 - A deprecated
-  [autotools](https://cppad.readthedocs.io/en/latest/autotools.html)
+  [autotools](https://cppad.readthedocs.io/latest/cmake.html#autotools)
   procedure can be used for this purpose, but it will eventually be removed.
 
-- For any sub-directory *dir*,
-  files of the form *dir*/`makefile.am` and *dir*/`makefile.in`
-  are used to support the Autotools test and install procedure.
-  In addition,
-  the following files, in this directory, are also for this purpose:
-  `compile`,
-  `config.guess`,
-  `config.sub`,
-  `configure.ac`,
-  `depcomp`,
-  `install-sh`,
-  `missing`.
+## Getting Started
+  [get_sarted](https://cppad.readthedocs.io/latest/get_started.cpp.html)
+  demonstrates using CppAD by computing the derivative of a simple example function.