Move tpl.php files to a templates folder in the root zen directory

As part of the general reorganization of the Zen project, it would be nice to have all the template files in one folder in the root zen directory.

That would make searching for the tpls and copying them to your sub-theme simpler.

There is the additional problem that we've got duplicate zen directories which has been a bit confusing. Which zen directory? zen/ or zen/zen/ ? :-p What's worse is when an unzip program creates a third zen directory to hold all the contents of the .tgz file. oof.

The easiest way to do that is to clean up the root zen directory and the bare necessity of files down from the zen/zen directory (like zen.info, template.php, and logo.png) and then rename zen/zen/ to zen/zen-internals.

Current root layout:

-rw-rw-r--   1 jwilkins  jwilkins  14081 Aug 12 00:37 CHANGELOG.txt
-rw-rw-r--   1 jwilkins  jwilkins   6315 Aug 11 23:25 README.txt
drwxrwxr-x  13 jwilkins  jwilkins    442 Aug 12 01:24 STARTERKIT/
drwxrwxr-x  22 jwilkins  jwilkins    748 Aug 12 01:25 zen/

Proposed root layout:

-rw-rw-r--   1 jwilkins  jwilkins  14081 Aug 12 00:37 CHANGELOG.txt
-rw-rw-r--@  1 jwilkins  jwilkins    941 Aug 11 23:55 logo.png
-rw-rw-r--@  1 jwilkins  jwilkins   1613 Aug 12 00:28 README-FIRST.txt
drwxrwxr-x  15 jwilkins  jwilkins    510 Aug 12 00:56 STARTERKIT/
-rw-rw-r--@  1 jwilkins  jwilkins   8777 Aug 12 01:03 template.php
drwxrwxr-x   8 jwilkins  jwilkins    272 Aug 12 00:58 templates/
-rw-rw-r--@  1 jwilkins  jwilkins   5545 Aug 12 00:50 theme-settings.php
drwxrwxr-x  12 jwilkins  jwilkins    408 Aug 12 01:04 zen-internals/
-rw-rw-r--@  1 jwilkins  jwilkins   1335 Aug 12 00:39 zen.info

This would actually give the Zen theme a more traditional appearance (compared to other themes). And the STARTERKIT would continue to work the same way; just copy it to a directory outside of zen/.