Start VS2012 solutions and projects
Add .sln and .vcxproj files for VS2012
Correct .lib name after $(ProjectName) changed
Update algorithms for Visual Studio 2012

Add forwarding from concurrency::samples::parallell_*  to
concurrency::parallell_* if VS2012 is detected.
VS2012 in <ppl.h> implements most of algorithms originally defined in
<ppl_extras.h>for VS2010.
This makes simplest update that allows to use ppl_extras.h with both
versions of Visual Studio.
Qualify parallel_transform to avoid name clash

VS2012 in <ppl.h> implements most of algorithms originally defined in
<ppl_extras.h>for VS2010.
samples::parallel_* forward to concurrency::parallel_* if necessary.