Merge branch 'master' of github.com:jleffler/scc-snapshots

When trying to push the 6.70 changes to the upstream, it refused to
allow the merge until conflicts were resolved.  This should resolve
those conflicts.

Author: jleffler

README.md

@@ -2,7 +2,7 @@
 SCC: Strip C Comments — Snapshots
 
 This repository contains the code for the SCC (Strip C Comments) program described in
-[Remove Comment from C/C++ Code](http://stackoverflow.com/questions/2394017/) on Stack Overflow.
+[Remove Comments from C/C++ Code](http://stackoverflow.com/questions/2394017/) on Stack Overflow.
 
 There are currently 6 releases:
 * 4.03 (2008-06-07)
@@ -13,3 +13,15 @@ There are currently 6 releases:
 * 6.60 (2016-06-12)
 
 These are tagged release/x.yz.  The code is all on branch master.
+
+Version 5.05 handles C and older C++ code.
+It does not understand raw strings, or some of the other new features in C++
+(binary constants, punctuation in numbers, etc.).
+
+Version 6.60 handles C and newer C++ code.
+It understands raw strings, binary constants and punctuation in numbers.
+It has a different, slightly more complex interface compared with version 5.05.
+
+Neither version handles trigraphs (and neither version needs to handle digraphs).
+There are separate programs for adding or removing trigraphs and digraphs (called,
+unimaginatively, `trigraphs` and `digraphs`).