[ISSUE] Remove/replace Simple_closure smob type

[David Kastrup]

Type: Maintainability
Owner: address@hidden
Status: Started
Patch: new
Rietveld issue: 262560043 (https://codereview.appspot.com/262560043)
Summary:
Remove/replace Simple_closure smob type

Consists of commits (including patch from issue 4618):

Rewrite call_pure_function


Remove node "simple closure" from notation appendices


Remove/replace Simple_closure smob type


Import grob::compose-function and grob::offset-function into C


Add grob::compose-function and grob::offset-function

Those are the main replacements for the uses of ly:make-simple-closure
in lily/grob-closure.cc.

Add ly:pure-call and ly:unpure-call functions


Remove unused function chain-grob-member-functions


Issue 4618: Correct argument handling of Unpure_pure_call::call

-- 
David Kastrup