Fix unit tests

Fixes problem caused by changing from services/add to services/deploy
when installing services.
Add getPath() routine to servicetree
Ensure nested services are processed in order

When adding or deleting services as part of zenpack operations,
ensure that the operations are ordered correctly so that parents
are added/removed before/after children
Add unit tests

Unit tests for testing nested service install/remove
Merge pull request #193 from zenoss/feature/nestedZenpackServices

Feature/nested zenpack services