*** ALPHA - Subject to change ***

  Loads data from an avro file. Returns data as maps with keyword keys
corresponding to avro field names. Fields with avro type 'map' will be maps with
string keys.

  Example:

    (pig-avro/load-avro "input.avro" (slurp "schemafile.json"))

    (pig-avro/load-avro "input.avro"
       "{\"namespace\": \"example.avro\",
          \"type\": \"record\",
          \"name\": \"foo\",
          \"fields\": [{\"name\": \"wurdz\",
                            \"type\": \"string\"},
                           {\"name\": \"bar\",
                            \"type\": \"int\"}]}")

  Notes:
    * Avro schemas are defined on the project's website: http://avro.apache.org/docs/1.7.7/spec.html#schemas
    * load-avro takes the schema as a string
    * Make sure a piggybank.jar (http://mvnrepository.com/artifact/org.apache.pig/piggybank/0.14.0)
      compatible with your version of hadoop is on $PIG_CLASSPATH. For hadoop v2,
      see http://stackoverflow.com/a/21753749. Amazon's elastic mapreduce comes
      with a compatible piggybank.jar already on the classpath.