DISCUSS - Removing Visual Studio 2010 and 2012

# Should we support VS2010 and VS2012?
So far I've left support for Visual Studio 2010 in place despite it definitely not compiling/linking or running anymore. This was just because someone might want to get it going with Boost or something again. However if people want to get it going again then they can always pull it out of the Git history (?).

Likewise VS2012 has been a pain with newer features like deleting copy constructors and `operator =` as well as a few other places. In fact I only noticed the other day that it was broken as I dutifully loaded it up and tried to get everything compiling again (#2768 & #2769) apparently no-one noticed that it was broken.

So I'm proposing that we just remove them. This would make Visual Studio 2013 Express Edition the easiest IDE/compiler for Windows developers - which is available for free from Microsoft.

There's also an alternative Windows compilers and IDE's in the form of Code::Blocks thanks to @Luomu too.