[boost] [boost.test] merging minor changes to master

31 Mar 2018

      Hi list,

I merged a very minor commit that will make MinGW people happy. Rev of 
Boost.test on master is now 413b2f660118060db732dbf38a2bdffb527395e3 .

Since Beta1:
* doc updates
* small bugfix PR 134
* include all lower case on windows for MinGW. PR 136

I would be grateful to the release managers if those changes go to the 
final 1.67 release.

Thanks,
Raffi

Raffi Enficiaud