added line numbers to generic log formatter
RFC 6585 HTTP Exceptions
did not include code 511 because it is for use by intercepting proxies
Allow the last callback called to add a callback

This fixes a bug in the finished and response callbacks where if the last/only callback adds another callback, the newly added callback won't be called afterwards.

This is because when it tries to add the callback, it is added to a new list instance because the callbacks list is empty at that time; the check for whether the callbacks list was created didn't previously distinguish between an empty list and not a list.  However, if it is not the last callback in the list, the callbacks list will not be empty and the new callback will be added to the same list and the newly added callback *will* be called.

Because the code as written appears to be trying to support callbacks adding callbacks, this push request modifies the code so that a callback may add another callback whether it is the last one or not.

An alternative approach would be to modify the code so that callbacks cannot add new callbacks, which also would be reasonable.  But I think it's a bug that the behavior depends currently on whether you are in the last/only callback when you try to add another one.
Allow hyphens in project name

Convert hyphens in project_name to underscores in pkg_name
Add a test case for a response callback adding a response callback when it is the only callback.
Add test_scaffold_with_hyphen_in_project_name
Use None for the default value of the callbacks list.
Use a deque for the request finished / response callbacks.
Fix a few tests that assume response_callbacks was a list
Minimize changes to increase merge likelihood
Link to .ini file description in configuration chapter.

The Startup chapter describes a Pyramid application's .ini file.
This is now a seealso in the Configuration chapter.
Link to logging configuration in the Startup chapter.

The Startup chapter describes the application's .ini file.  The
Logging chapter describes how to configure logging with the .ini file.
Add index entries for .ini files vis settings.
Some improvements to the paste.translogger related docs.

Synchronizes with Waitress docs.
remove unnecessary use of `get_current_registry()`

- We have a request object, so get the current registry
  properly through it.
- make use of the built-in `aslist` function for parsing the result
Merge pull request #1400 from tisdall/doc_update

remove unnecessary use of `get_current_registry()`
Enable automated testing with PyPy 3
Merge pull request #1403 from frewsxcv/patch-1

Enable automated testing with PyPy 3
- add missing step for tox setup