Add unit tests for vg.number .
Add unit tests for 'vg.extend' .
Add unit tests for 'vg.duplicate'.
Format source code.
Add unit tests for 'vg.field'.
Merge remote-tracking branch 'upstream/master' into package-test
Add unit tests for 'vg.accessor'.
Add unit test for 'vg.comparator'.
Merge pull request #30 from lgrammel/package-test

Added unit tests for the remaining non-trivial methods in _package.js. Thanks!