[CppAD] cmake install procedure

[Brad Bell]

The old unix install procedure
     http://www.coin-or.org/CppAD/Doc/installunix.xml
has been deprecated. You may however have to use it to test and install 
old versions of CppAD.

The new procedure uses cmake to configure CppAD; see
     http://www.coin-or.org/CppAD/Doc/cmake.xml
and the recent headings on
     http://www.coin-or.org/CppAD/Doc/whats_new_12.xml

All of the tests run (and pass without error) on my Windows 7 Visual 
Studio 2010 system (using nmake makefiles). CMake also provides a GUI 
for configuration and can be used to generate Microsoft project files 
(as well as nmake files). See
     http://www.cmake.org/cmake/help/install.html