ConfigOption documentation and name changes

* Expanded and updated someConfigOption description strings in
  GraphDatabaseConfiguration

* Renamed merge-basic-metrics to metrics-merge-stores

* Renamed machine-id-appendix to unique-instance-id-suffix

* Modified ConfigurationPrinter to preload ConfigOptions in the
  classpath via reflections before iterating over the config object
  tree; extracted this logic into a helper class now that it is used
  in two places (ConfigurationPrinter and TitanFactory)

* Added PreInitializeConfigOptions to some classes in the
  storage/index backends

* Tweaked the AsciiDoc->DocBook stylesheet to break extremely long
  single-word default value strings instead of making the table run
  off the right side of the screen
Merge branch 'titan05' of github.com:thinkaurelius/titan into titan05