Add pad for a combining character appearing by itself.
Add pad for a combining character appearing by
itself.

sanskrit-coders/m17n-db,sanskrit-coders/m17n-db,xmirror/m17n-db,xmirror/m17n-db,xmirror/m17n-db,xmirror/m17n-db,sanskrit-coders/m17n-db