Add project drawer for directory tree navigation

I feel kinda bad about this. I really should learn ECB or dired (or
both), but I have stuff to do and NERDTree was something of which I had
only learned just enough to navigate, create, rename, and delete files
and folders. I used it like maybe twice a day. So, I punted and
installed neowin, which appears to be a fairly close to NERDTree.

I won't say much about it -- just that the main keys I need are:

* <leader>p - toggle the neowin sidebar (my mapping)
* <leader>P - open neowin and highlight the current file (my mapping)
* C-c C-n   - create a new file or folder
* C-c C-r   - rename (move) a file or folder
* C-c C-d   - delete a file or folder
Add neowin post
Two spaces for tabs, backup files, other refinements

Here comes a grab bag of goodies. I'll just hit them quickly.

* Fixed my <leader>r and <leader>y mappings so they include files
  outside the current project
* Put backup and autosave files in ~/tmp so they don't litter all my
  projects
* Map C-r to redo, like in Vim
* Add a function and mapping <leader>fr to send signal via MozRepl to
  Firefox telling it to reload the current page (poor man's LiveReload)
* Set default soft-tab widths to 2 spaces
* Make it so <enter> auto-indents
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