I would like to merge the mpl 'develop' changes to mpl 'master'. The develop changes have cycled long enough IMO for the merge to take place, without any problems showing up in the changes. There are two changes of my own and a number of Stephen Kelly eliminating support for very old compiler versions. The changes will clean up many obsolete workarounds for older versions of compilers that no one doing template metaprogramming should seriously use anymore. My own two changes fix some minor problems I ran into when testing clang with VC++ RTL on Windows. The changes make the MPL easier to understand. If there are no objections to the merge I will be glad to carefully do it myself, or Dave Abrahams/Alex Gurtovoy or others who have write access to MPL can do it. But I think it is important to get these changes into 'master', and tested in the 'master' regression tests, before the next Boost release.