added atom/residue offset/end/count getters to chain proxy
added atom/residue offset/end/count getters to chain proxy

arose/ngl,j0kaso/ngl,arose/ngl,fredludlow/ngl,arose/ngl,fredludlow/ngl,fredludlow/ngl,fredludlow/ngl,j0kaso/ngl,arose/ngl,j0kaso/ngl