pass the context to extra_context functions

[bennydaon@…]

I found it helpful for extra_context functions to have access to the context.
The change is in line 80:

<        if callable(value):
<            c[key] = value()

>        if callable(value):
>            c[key] = value(c)

I'm not sure who decides on whether it should go to the version - it does changes the API

[Malcolm Tredinnick]

(Fixed description formatting.)

What file are you trying to change here? What is an example use-case?