Tabled tab completion now includes divider row.
Tab completion results for aliases, macros, and Settables wrap long fields.
SimpleTable now accepts blank for the divider character. It is identical to passing None.
Removed --verbose flag from set command so the descriptions always show.

(Cmd) set --long
Usage: set [-h] [-v] [param] [value]
Error: unrecognized arguments: --long

# Conflicts:
#	docs/features/settings.rst

- In docs/api/cmd.rst, the `cmd2.Cmd` class was defined as `cmd2.cmd2.Cmd`, which required the extraneous `cmd2` every time we referenced it. This extra `cmd2` is no longer required.
- always refer to a bare cmd2 using ``cmd2`` per our documentation conventions

The 3 attributes are:
- continuation_prompt
- locals_in_py
- prompt