Allow service modified, to reduce service stampede (Although at this point, I don't think there are many services persistently depending on a datasource)
Implement multi-instance datasources.

Now, a datasource can be resolved under multiple datasources.
For this, the 'unique datasource' property must be established, right now that is: url|username
So if the username and the url are the same, different datasources will be resolved to the same
connection pool.
Merge branch 'master' of github.com:Dexels/navajo

Closes #230