adding rexpro meta container and field definition classes
adding static define method to meta field
adding Meta field to RexProMessage
adding Meta field definitions, and getters and setters for the script and session request messages
changing field definitions to getter
refactoring filters to work with meta field
refactoring various classes to work with rexpro meta field
adding rexpromessage meta class and special msgpack template to allow it to serialize/deserialize Object values
updating message creation to work with updated message meta setup
folding meta serialization template into a nested class on RexProMessageMeta
adding tests around message serialization and meta validation
Merge remote-tracking branch 'bdeggleston/master'
Minor refactoring and bug fix in rexpro.

Had to iterate the results from pipeline into a list or else the iterator got exhausted and no results returned...i think.
Add init script.
Add support for chkconfig.
Add installation instructions.
More instructions.
Allow third-parties to plug-in new gremlin flavors.
Removed rexster.xml as the final fallback in configuration.
Exposed the option to override log4j.properties.