video metadata write support development branch created

git-svn-id: svn://dev.exiv2.org/svn@3096 b7c8b350-86e7-0310-a4b4-de8f6a8f16a3
add licence and fix TYPO

git-svn-id: svn://dev.exiv2.org/svn@3097 b7c8b350-86e7-0310-a4b4-de8f6a8f16a3