ThreadLocal cleanup

This commit removes ThreadLocal usage from KryoSerializer and
CTConnectionFactory.  The KryoSerializer ThreadLocal caused problems
with Tomcat (#877).  CTConnectionFactory's ThreadLocal seems to
produce a unmeasurably-small performance gain, if it produces one at
all, so I replaced it with an ordinary private final field.
Remove unused field in KryoSerializer

c4c72ab3d978f5a5a8515365ecc429fe70215b02 appears to have removed the
last use of KryoSerializer's private 'registrations' field.  It's not
used as of this commit.
add cfg opt for sleep time after ES index creation

The Elasticsearch adapter had a hardcoded 200 ms sleep after creating
an index.  This is now configurable through
index.[X].elasticsearch.index-creation-sleep.  The default remains
unchanged (200 ms).
Add ES replica/shard count options

This allows the Titan configuration to supply arbitrary key-value
settings passed to the Elasticsearch cluster when creating an index
during DB bootstrap.  This commit reuses the configuration handling
code introduced in 304f14e44f986e806ac8e86437ff7b8e46a68045, except
this commit controls index creation settings, whereas that prior
commit controls client settings.

This commit introduces two new config elements:

* index.[X].elasticsearch.create.ext (namespace)
* index.[X].elasticsearch.create.conf-file (string opt)

This commit also changes the option named
index.[X].elasticsearch.index-creation-sleep (just introduced in
979eb87d89bd019f20f82ed6ebf98842a24d3f2c) to
index.[X].elasticsearch.create.sleep.

For #840
Deleting the ES index creation conf-file option

This option was analogous to the client settings conf-file option,
except this one controlled settings specific to the request Titan
sends to create an index in ES.  Not worth adding another conf-file
option for this, particularly before the relative-path hack for
conf-file options is cleaned up and integrated into the ConfigOption
system.

For #840
AsciiDoc for new ES index creation customization

This documents the changes in 6569f8b060a86a6291326e76f5dbe612732b2f7f
and f3f79b6120736d30f442f78d59eb62efe8a8d4dd.

It doesn't mention the sleep time setting introduced in
979eb87d89bd019f20f82ed6ebf98842a24d3f2c.

For #840