bash: Set terminal title in custom prompt

Rather than using `PROMPT_COMMAND` (which can be slow, apparently), use
the custom `PS1` to set the terminal title string.
osx: Additions and improvements to OS X defaults

Harvest some of recent changes and fixes from @mathiasbynens's dotfiles.

Make the `osxdefaults` script automatically kill the affected
applications.

Reformat for easier reading.
Add list of additional software to install

A list of software/apps that I like to install on a new machine.

Display the list of additional software when the `-l` or `--list` option
is passed with the `dotfile` command.
Add `--list` option to README
bash: Add `inputrc` options

* Case-insensitive TAB autocompletion
* TAB cycling through possible completions
* More powerful previous-command searching
Pull in changes and a few edits