avro

AVRO-762. C: Promotion of values during schema resolution

The avro_resolver_new function now takes into the schema promotion
rules: an int can be read as a long, float, or double; a long can be
read as a float or double; and a float can be read as a double.  The
test_avro_data test program includes test cases for each of these
promotions.


git-svn-id: https://svn.apache.org/repos/asf/avro/trunk@1074614 13f79535-47bb-0310-9956-ffa450edef68