Separated apply_current_directory and apply_view in Wrangler asset code.

OLD: Wrangler._make_asset_menu_entries() featured only the keyword
apply_view=True.

NEW: Wrangler._make_asset_menu_entries() features both apply_view=True and
apply_current_directory=True. The two keyword function indpendently.
apply_current_directory=True constrains list elements to things in the current
directory (ie, to in-score assets as opposed to the entire systemwide library
of assets); apply_view=True constrains by any view that is applied.