[ansel] Ansel VFS structure

[Ben Chavet]

After working on this for a bit, here's what I've come up with:

Option 1:
   ansel/hash/full/image
   ansel/hash/screen/image
   ansel/hash/thumb/image

   lets us use $view in the path.  This leads to clean & efficient code
   because we don't have to do any tests.  It will be harder to use a
   command prompt for this, but it would be easier for backups.


Option 2:
   ansel/hash/image_full
   ansel/hash/image_screen
   ansel/hash/image_thumb

   is simple, doesn't require tests and has a shorter path.  This puts
   more files in a directory, but that could be worked around with a
   hash with fewer collisions.  It will be easier to use a command prompt
   with this structure, but backups would be trickier if you only want
   to back up full images.

Option 3:
   ansel/hash/full/image
   ansel/hash/created/image_screen
   ansel/hash/created/image_thumb

   requires a lot of extra testing.  We have to check if we are doing a
   full image for everything so we get the right path and image extension.
   I'm leaning pretty heavily away from this option because of code
   complexity.


So, it really comes down to what is more important:  Easier backups (Option 1)
or easier command-line access (Option 2).

I rarely use the command prompt to work with images, unless I'm doing
development (in which case, I use 'rm -rf .horde/ansel' more than anything).  I
don't see the average admin doing much command-line work in ansel, either.

I haven't done any backups on my photos, but I think this would be more
important to the average admin.

Thoughts?

--Ben