Made a start with api.tex, the Python-C API Reference Manual.
Removed extref.tex (which provided the starting point).
Also removed qua.tex, which is out of date and no longer needed.
diff --git a/Doc/ext.tex b/Doc/ext.tex
index cf39f39..b32702e 100644
--- a/Doc/ext.tex
+++ b/Doc/ext.tex
@@ -1366,7 +1366,7 @@
 files).  No \samp{-l} options can be used.
 
 
-\input{extref}
+%\input{extref}
 
 \input{ext.ind}