[dna-dev] Restructured and renamed some Maven projects

We've made a few changes to our Maven projects that will impact your local environments. 1) The 'dna-spi' project has been renamed to 'dna-graph', and the package structure has changed significantly. 2) The 'dna-example-java-sequencer' project (under 'docs/examples/ gettingstarted') has been removed, and it's contents incorporated into the 'sequencer' example project. 3) The 'org.jboss.dna.common.util.ArgCheck' class has been renamed to 'CheckArg', making it more readable when used. Two of these changes have impacted a large portion of the codebase; please be aware of this when you next update from SVN. Also, you may want to delete from your local Maven repository (e.g., "~/.m2/ repository") the snapshot artifacts for these two renamed/deleted projects, just to make sure you don't accidentally use them. Thanks for your patience as we adapt to changes. Best regards, Randall