[boost] [COre] Pull request for enable_if_type

Subject: [boost] [COre] Pull request for enable_if_type
From: Joel FALCOU (joel.falcou_at_[hidden])
Date: 2015-08-10 10:57:58

Hi,

I just refurbished and pushed an old patch adding the enable_if_type 
SFINAE utility  to core.

https://github.com/boostorg/core/pull/15

I tried to keep it simple and make the doc proper. This utility has been 
laying around various boost library and was "reinvetned" in bosot.SIMD. 
I think it's worth being in core so code duplication is kept to a minimum.

Comments welcome