fix to alloy deeper database references

This is an important fix that allows the database file reference to be for example:

`/databases/database.sql`

or

`file://localhost/Users/david/Library/Application%20Support/iPhone%20Simulator/6.1/Applications/9D1B9309-4E51-4FB2-A625-ED271FDECC31/Documents//AlloyTest//myapp.sqlite`

Will fix this TiShadow issue: https://github.com/dbankier/TiShadow/issues/78