Modernizing Avro C++ binding

[Thiruvalluvan MG]

Hi all,
In the past 10+ years C++ has evolved to be a very new (and much better) 
language, still maintaining compatibility with the old. Some call it "Modern 
C++". Avro C++ implementation is still mostly in C++03 era.
I'm planning to send a series of patches to C++ implementation to use the 
modern features.
Please let me know if there are any concerns.
Thank you,
Thiru