Attempt proper gem builds on mri and jruby.

Squashed commit of the following:

commit 3c9881add0d9b2d46d14f1db47c6f808e3f33b62
Author: tbdev <chad.lancour@oracle.com>
Date:   Mon Mar 3 14:40:15 2014 -0800

    Attempt proper gem builds on mri and jruby.

    rake clean clobber
    rake compile
    rake gem

    * .gitignore
    excluding lib/racc/cparse-jruby.jar, racc.gemspec(in general, not present), racc.gemspec

    * Manifest.txt
    replaced lib/racc/cparse.jar with ext/racc/com/headius/racc/Cparse.java

    * Rakefile
    mimic nokogiri's rakefile process via add_file_to_gem
    removed requirement for maven build via Rake::JavaExtensionTask
    cleaner jar name
    refactored for java? jruby?
    hoe to HOE
    added Hoe.plugin :gemspec to allow one-off rake gem:spec

    * src/main/java/com/headius/racc/Cparse.java -> ext/racc/com/headius/racc/Cparse.java
    moved src/main/java/com/headius to ext/rac/com/headius to accomodate Rake::JavaExtensionTask

    * lib/racc/parser.rb
    match up require to jar file

    * pom.xml
    no longer nessecary