App socket. Persistent command history. Breakage.

- First commit in over a month, alas.
- Upgraded AngularJS version to angular-1.3.0-beta.17.
  - Use the new "watch once" ("{{::watch_me_once}}") facility where possible.
- Upgraded to ui-bootstrap-tpls-0.11.0.js.
- Much general refactoring and code movement. e.g. More directives and controllers.
- Probably some features added, and bugs fixed (or introduced, alas) that I've missed.
- Generally moved away from REST resources, all of which require a new connection to the server, in favor of a single app-wide control socket.
- Use sqlite for most persistent data (though not $HOME/.ntlarc.js).
- Added a pager to split up history into pages.  Currently each page holds only 5 command, but that'll go up later.
- See directories used by other tabs/clients in the recently used directory dropdown.  The list is persistent.
- Save commands run, and their output and other meta-data (start time, status code, etc), to disk (in the above-mentioned sqlite DB), and reread it on browser page reload.  There is currently no "user-space" facility to clear the log.  You have to drop the database (which of course deleted *everything*, not just the command history), or truncate the tables.
- Buttons to hide some or all output.
- Added a random query string to the app/<file> request, to avoid browser caching.  Sometimes "cache: false" seemed to work and sometimes not, and I got tired of fiddling with it.
- Added the 'c' hotkey to focus the directory input box.
- Removed the so-far-stillborn statically-placed up/down buttons to scroll command history.  Use the pager, instead.
- Configure the port the server listens to on the command line.
- .gitignore: updated .goplay tree; added ntla.db, the new sqlite db file

JS & Go commands are broken.  It might be a simple fix.  But I haven't committed in over a month and wanted to go ahead and get this saved.  It's a dev branch and (more importantly) I have no customers (watchers, stars, or forks), so I'm not hurting anyone, as near as I can tell.