Add csv-mode.el.
* packages/csv-mode/csv-mode.el: Minor installation cleanups.
Fix up copyright notice.  Set version.
(csv-separators, csv-field-quotes): Fix calls to `error'.
(csv-mode-line-help-echo, csv-mode-line-format): Replace mode-line-format
for default-mode-line-format.
(csv-mode-map): Declare and initialize.
(csv-mode): Add autoload cookie.
(csv-set-comment-start): Make sure vars are made buffer-local.
(csv-field-index-mode, csv-field-index): Use derived-mode-p.
(csv-align-fields): Improve insertion types of overlay's markers.
csv-mode.el: Improve commentary.
Commentary tweaks for csv-mode, ioccur, and nhexl-mode packages.
Commentary fix for quarter-plane.el.
* csv-mode.el: Use lexical-binding.  Remove redundant :group args.
(csv-separators): Add TAB to the default.
(csv-invisibility-default): Change default to t.
(csv-separator-face): Inherit from escape-glyph.  Remove variable.
(csv-mode-line-format): Remove trailing "--".  Move next to line-number.
(csv-interactive-args): Use use-region-p.
(csv--column-widths): New function, extracted from csv-align-fields.
(csv-align-fields): Use it.  Use whole buffer by default.
Use :align-to and text-properties when possible.
(csv-unalign-fields): Also remove properties.
(csv-mode): Truncate lines.
* csv-mode.el: Bump version number.
* packages/csv-mode/csv-mode.el (csv-end-of-field): Don't skip TABs.
(csv--skip-regexp): Rename from csv-skip-regexp.
* csv-mode.el (csv-kill-one-field): Check for presence before deleting trailing
separator.  Remove last arg and turn into a function.
(csv-kill-one-column, csv-kill-many-columns): Adjust callers.
* csv-mode (csv-mode-line-help-echo): Remove.