[C++] Increment minimum required CMake version to 3.1.3.
[C++] Increment minimum required CMake version to 3.1.3.

This is the minimum version that supports setting C and C++ standards.

marksantos/simple-binary-encoding,real-logic/simple-binary-encoding,marksantos/simple-binary-encoding,marksantos/simple-binary-encoding,PKRoma/simple-binary-encoding,marksantos/simple-binary-encoding,PKRoma/simple-binary-encoding,PKRoma/simple-binary-encoding,real-logic/simple-binary-encoding,marksantos/simple-binary-encoding,marksantos/simple-binary-encoding,real-logic/simple-binary-encoding,real-logic/simple-binary-encoding,real-logic/simple-binary-encoding,marksantos/simple-binary-encoding,marksantos/simple-binary-encoding,real-logic/simple-binary-encoding,PKRoma/simple-binary-encoding,real-logic/simple-binary-encoding,PKRoma/simple-binary-encoding,PKRoma/simple-binary-encoding,PKRoma/simple-binary-encoding