utilities/migrate/migrate.js to upgrade backup data to current bhima.sql build

In this pull request:
1. migrate.js corrects for column name changes in bhima.sql for current dropbox datasets
2. bhima.sql foreign keys for pc_id lifted to allow building the current dataset.

Usage:
```bash
# unzip bhima_$timestamp.sql into in.sql
node migrate.js in.sql out.sql
mysql -u root -p
# enter password
source server/sql/bhima.sql; source utilities/migrate/out.sql;
```