Added JUnitBenchmarks output to .gitignore
Centralize src/main/resources in titan-core

Redundant, identical copies of titan.properties and log4j.properties
in multiple modules is a maintenance hazard.  There's no reason to
have multiple copies.  Now it's in titan-core.
Merge branch 'master' of github.com:thinkaurelius/titan
Make slf4j-log4j12 and log4j optional (fixes #280)

* moved logging dependencies from titan-core pom to top-level pom
* made log4j & slf4j-log4j12 optional and runtime-scoped
* slf4j-api is still a normal dependency (non-optional, compile-scoped)
Update Lucene to 4.4.0 and ES to 0.90.5
Add client-side ES version check (fixes #338)

At compile-time, Titan's ES version is written to titan-es.properties.
The properties file gets included in the titan-es jar.
ElasticSearchConstants loads the properties file at runtime using
getResourceAsStream(...), just like TitanConstants.
ElasticSearchConstants then converts the version into a public static
final field on ES's Version class and loads that reflectively.
Finally, ElasticSearchIndex compares this expected version against
Version.CURRENT at runtime and logs a warning if they don't match.

Note that a version mismatch does *not* throw an exception.  It just
logs a warning.

This is all hideous and byantine and awful.  I wish there was an
easier way to check the ES version using only strings.  It's so easy
to get the cluster's version using the REST HTTP API, but I don't see
an equivalent way to do it with only the Java API, and I don't want to
add a whole second client to the ES index implementation just to read
a 6-byte version string.
Merge branch 'master' of github.com:thinkaurelius/titan