add OR2_IO_DEFAULT to r2context
add OR2_IO_DEFAULT to r2context

git-svn-id: e22e7ba13cdef0ce65536ff79bba069cc1048473@168 c87312dc-f89b-4d16-81b4-35530099f826

moises-silva/openr2,moises-silva/openr2,moises-silva/openr2