Update AbstractPluginManagerModel.php

This fixes two issues:
1. The previous behavior would overwrite keys because of the array addition which could potentially cause less hydrators to show than really available.
2. It uses the getCanonicalNames() method of the service manager to return the full display name which makes it a lot easier to view in the dropdown.
Merge pull request #66 from spiffyjr/patch-1

Update AbstractPluginManagerModel.php
Update AbstractPluginManagerModel.php

Include invokables via reflection. This should be patched in develop at some point to allow access via an accessor.
Merge pull request #66 from spiffyjr/patch-1

Update AbstractPluginManagerModel.php
Updated select box for hydrators

- As we now have a straight array, not an object
Updated filter and validator metadata

- Now that we have the actual service name, not the "canonicalised" version, we
  can map by class.
Merge branch 'hotfix/66'

Close #66

Thanks, @spiffyjr !!!