-Added a voldemort client shell with suport for avro stores

- testing done:

for a store with schema

<key-serializer>
      <type>avro-generic-versioned</type>
      <schema-info version="0">"string"</schema-info>
    </key-serializer>
    <value-serializer>
       <type>avro-generic-versioned</type>
      <schema-info version="0">"string"</schema-info>
    </value-serializer>

operations would be:
put "a" "b"
get "a"
The regular expression did not work for reords and unions