first pass of marshal-ing code.

Few failures remain.
add indices.md
set up basic API for Ramsey::Index, remove old code from ramsey/index.rb
configure path, not name, in config block.
rough in the index
spec Ramsey::Index#delete!
spec Ramsey::Index#update!
rough in Ramsey::Index#load! specs
Implement #load! on Index
implement #save! on index

needs integration specs
factor fixture stuff into a shared_context
add integration spec covering dumping an index to file and reloading it.
extend the save and load spec to cover multi-property indices.
implement #delete on Index

Also implements the UUID Cache on the index, the tests aren't great, but passable for the moment
add some notes about things to do to the Index class
Use Set instead of Array
use Set#delete instead of #reject!
disable some tests till Indexer/BTree extraction is done
remove errant spec file
implement a Vector(n) parameterized class, with Shotgun testing

Shotgun Testing is a form of randomized testing similar to that of QuickCheck from
Haskell-land. You can turn it on by setting SHOTGUN_TESTING=<something> and running the
normal rake spec task. It's implementation is trivial -- it's just an `if` block that 
checks to see if the env-var is set, and executes some metaprogrammed tests if it is.

With this, we randomly sample vectors of different order and make property-based assertions
about them. This case is pretty trivial, it's unlikely that a vector of order `n` won't work,
if a vector of any smaller nontrivial order does, but this way we can sample a large space
of vectors and ensure that's true. For more nontrivial classes -- eg, a red-black tree, or
a b-tree, shotgun testing can ensure that there is no order-specific code that would possibly
break if the order changed.