Changing from the existing method of adding built in labels at server startup.
This new method should be friendlier to long term changes, and falls in line
with the new pattern established for osquery options.
Fixes#702
This PR separates the table migrations from the data population migrations. Table migrations run before data migrations.
Now, we have the ability to create the database tables without populating them with data. This can be useful for running "unit" tests against a MySQL store that doesn't have any pre-populated data. When performing real migrations, or for more "integration" style testing, the data migrations can also be executed.
Note there are some special cases that must be observed with these migrations, and the README is updated to reflect those.
