Added support for BaseSequentialStream to the C++ wrapper.

git-svn-id: https://chibios.svn.sourceforge.net/svnroot/chibios/trunk@5022 35acf78f-673a-0410-8e92-d51de3d6d3f4
Missing virtual...

git-svn-id: https://chibios.svn.sourceforge.net/svnroot/chibios/trunk@5023 35acf78f-673a-0410-8e92-d51de3d6d3f4