Backwards compatibility for Tomcat module Pillar configuration

Updated the Tomcat module and docs so 2014.7 supports the previous configuration format for pillar.

## New Format ##
```
tomcat-manager:
  user: <username>
  password: <passwd>
```

## Old Format ##
```
tomcat-manager.user: <username>
tomcat-manager.password: <passwd>
```

I've added a simple test for this when running the module from the CLI, but a unit test would be more appropriate.