Wangle codec addition

[claudiouzelac]

This pull request adds support for compiling the Wangle, codec. The codec is needed for the examples such as the echoserver which is included in the update.

[claudiouzelac]

Looks like an unrelated error:

/home/travis/build/mzhaom/trunk/third_party/java/grpc-java/BUILD:5:1: C++ compilation of rule '//third_party/java/grpc-java:grpc_java_plugin' failed: gcc failed: error executing command /usr/crosstool/v2/gcc-4.9.2-lrtev2/x86/bin/gcc -Wall -Wno-sign-compare -Wno-unused-local-typedefs '-Wno-error=unused-local-typedefs' -g0 -O3 -DNDEBUG -ffunction-sections -fdata-sections ... (remaining 28 argument(s) skipped): com.google.devtools.build.lib.shell.BadExitStatusException: Process exited with status 1.

I'll try to repro locally.