Remove unused records
Unused variable
Perform add + delete in same request

Yokozuna needs to perform both a delete and add for each index
operation.  This is needed to make sure siblings are handled properly
[1].  Currently this is done as two separate HTTP calls.  This patch
combines both into one.

On my MacBook Pro I saw a ~15% improvement in throughput, a 11ms
drop in median latency, and a 15ms drop in 95th latency.

Additionally, I cleaned up the delete API.  There is now just one
function to delete.  A list of `delete_op()` is passed and `yz_solr`
will handle encoding it into JSON.  Added `yz_solr:index/3` so that
delete ops can be sent along with doc additions.

[1]: In the future perhaps we can be smarter about this and add some
type of hook into KV that notifies Yokozuna when a) siblings have been
created or b) when they have been resolved.
Remove unused functions

The boost stuff was a holdover from a copy/paste job I did a long time
ago.  Index boosting is not supported in Yokozuna.
Fix field name
Fix `sync_data`

I forgot to update the `sync_data` function for the new one-to-many
indexing feature.  When removing an index association from a bucket a
query delete must be sent to the index (not an index with the same
name as the bucket) to remove all documents with a matching bucket
(`_yz_rb`) field.

Send a commit after the query delete.  During testing I found that
some or all of the trees would get rebuilt before the query delete
took affect (the default 1s soft-commit).  Thus the test would fail
because it would have to wait for the trees to expire which defaults
to a week.  Instead, I thought it wouldn't hurt to run a commit after
the delete.

Added an additional check to the flag transition test to verify that
on adding a flag all entries are deleted from the default index.
Add test for one-to-many index + bucket transitions

Add a test to make sure that an index with many associated buckets
only has a subset of it's data deleted when the association is removed
from one of the buckets.

* Move `http_put` to `yz_rt`.

* Add sleeps to `yz_errors` to account for soft-commit.
Remove unused variable
Merge pull request #48 from basho/rz-delete-update-same-req

Send Delete & Update in Same Request