'tiles' should be modular to allow easy UI customization

[7yl4r]

I've been going back and forth on this a bit, but I think I have a good sense of how to structure the tpl-based page-maker engine. Here are the key aspects:

• UI elements common to multiple pages (like the left navigation and top status bar) should be defined in their own .tpl for easy inclusion and minimal code duplication
• specific content "tiles" in the main content section should be defined in their own .tpl so that "drag-and-drop" is as easy as doing an include('tile1') in a new page.
• generalizable tile formats like imageText.tpl which specifies an image + description and tile_overview.tpl which specifies an image + column of short statements set off by
  should be used whenever possible to create the "specific content tiles" mentioned above.

Put another way, consider the following template-within-template hierarchy, where lower-level tpl files are used to build higher-level tpl files:

1. page-level tpl specifies template for building a full html page
2. UI element / content tile tpls specify drag-and-drop parts of a page
3. general element / tile tpls allow for easy creation of new modular page-parts

The code is partially there, but there is a bit more to do before it is done. Once it is, I suppose there should be a wiki page explaining this for future template-ers. That is how I think it should work, but I'd love to hear some more thoughts and opinions.