Add protobuf-to-jsoncpp

Imported from [https://code.google.com/p/protobuf-to-jsoncpp/]
Add jsoncpp submodule, remove protobuf-to-jsoncpp
Add cmake jsoncpp find module
Add jsoncpp compilation to bootstrap
Big chunk of work on async server handler and codecs

- wire open/close/call promitives, enumeration
- protobuf state initialized from FileDescriptorSet
- wire <-> protobuf <-> json codec
- async cpp-netlib server
- async processing of device communication
Simple testcase for protobuf codecs

- includes fixture data generated from python-trezor test suite
Update cmake