Moved some functions from 'Context' to 'Local_context'

This is one step in order to eliminate 'Context' in its current
setting.

	modified:   ocaml/context.ml
	modified:   ocaml/eiffelc.ml
	modified:   ocaml/local_context.ml
	modified:   ocaml/local_context.mli
	modified:   ocaml/typer.ml