[Evolution] evolution folder layout

["Matt Loper" <matt helixcode com>]

In case people haven't caught on, we'll be using a directory to store
Evolution-related data. Here's a first-cut idea of what such a thing might
look like. Comments welcome.

evolution
  |
  |- shortcuts
  |   Main_Shortcuts.xml
  |   Other_Shortcuts.xml
  |
  `- folders
      |
      |- My_Contacts
      |    Book.db3
      |    Book.metadata
      |    Icon.png (Icon.png files are optional)
      |
      |- Inbox
      |    Mail.mbox
      |    Mail.summary
      |    Mail.ibex
      |    Mail.metadata
      |    Icon.png
      |
      |- My_Calendar
      |    Calendar.cal
      |    Calendar.metadata
      |    Icon.png
      |
      `- Trash
          |
          |- Calendar
          |- Mail
          `- Contacts

Notes:

* The xml files under the "Shortcuts" directory would contain viewable names
and uri's (most of which may point to stuff in the "folders" directory).

* A metadata file can store the goad-id of a control, a pointer to an icon,
saved view-related information, the type (mail, calendar, addressbook) of
info viewed, etc.

* One rule we'll probably make about a folder is that although it can
contain other folders of any type, it can itself only store one type of
item. This is why the "Trash" directory contains directories under it, each
of which is a specific type.

-Matt