Merge branch 'master' into fairchild

Merge branch 'master' into fairchild

* master: (21 commits)
  dot/ipython-key-bindings.py: Fix because IPython is now (fr)agile.
  dot/zshrc: Fix path ellipsization in the prompt.
  dot/emacs-calc: Add peta- and exa- prefixes for bits and bytes.
  el/dot-emacs.el: Add a useful `w3m' binding to open links in new tabs.
  dot/gitconfig.in: Don't have `git send-email' try to do threading.
  dot/gitconfig.in: Abolish the `git email' alias.
  dot/gitconfig.in: Remove output filename; force full indices.
  git/gitignore: Ignore toplevel `p/' and `p.*/' directories.
  git/gitignore: Only ignore `build' etc. if they're toplevel directories.
  git/gitignore: Deprecate `deb-build/' and `build-*/' directories.
  dot/gitconfig.in: Configure `format-patch' to do sensible things.
  el/dot-emacs.el: Override git's use of a pager more vigorously.
  dot/zshrc: Don't have `typeset -x' implicitly make variables global.
  el/dot-emacs.el: Suppress `/dev/null' filename when running `git grep'.
  dot/zshrc: Recognize the keypad keys.
  dot/zshrc: Commentary for running `~/.zshrc-local'.
  dot/zshrc: Interpret `**' to cover files too, where sensible.
  dot/zshrc: Include parser content in the second-level prompt.
  dot/shell-rc: Add a hook for shell-specific `PS2' customization.
  dot/shell-rc: Don't expand `TERM' or `INSIDE_EMACS' if they're not defined.
  ...