CLI Delete/Show grammar extension for collection.

Extends the grammar for the CLI Delete and Show commands to handle
- show a field for object collection, and
- delete elements in a sub-collection under a top-level collection.

-Sample CLI inputs-
**To show the VTEP name**
> vtep management-ip 119.15.112.22 show name

**To delete bindings**
> vtep management-ip 119.15.112.22 delete binding vlan XXX
> vtep management-ip 119.15.112.22 binding delete network-id YYY

Note:
- The above delete commands can delete multiple resources (bindings).
- To delete, at least 1 or more filters (e.g. vlan id, network ID)
  need to be specified. The following delete-all command is invalid:

> vtep management-ip 119.15.112.22 binding delete

Fix MN-1824
Merge pull request #183 from midokura/dev/tomohiko/mn-1824-coll-filter/20140616

CLI Delete and Show grammar extension for collection.