Fix compilation with Visual Studio 2013

The <algorithm> header is needed for std::min and friends,
and the CMakeLists.txt modification makes the version check
match what is used in the source code.

Unfortunately cmake does not seem to contain a GREATER_OR_EQUAL
macro, so NOT(LESS) has to be used.

--HG--
branch : stable
slicetype: bug fix for estimated frame costs

By the time rate control queries the estimated frame cost, lastNonB might have
moved.  Use the slice's actual L0 reference.

--HG--
branch : stable