* grpc_server_request_call
* basic slice functionality
* rename function to emphasize side effects
* add docs
* ByteBuffer function bindings
* replace unsafeCoerce with more specific function, add docs, tests.
* add newtypes for Tag and Reserved void pointers
* manually fix request_registered_call binding
* use nocode keyword to fix Ptr () problems
* decouple copying Slice from freeing slice
* Add time ops
* remove nocode decls
* Start Op module, fix c2hs preprocessing order
* metadata manipulation operations
* metadata free function, test
* helper functions for constructing ops of each type
* bindings for op creation functions
* finish up Op creation functions, implement Op destruction, add docs.
* tweak documentation
* rework Op creation functions to work with an array of ops, for ease of use with grpc_call_start_batch
* forgot to change return types
* wrap hook lines, fix types to op creation functions
* implement part of the payload test
* hideous, but working, end to end test
* bindings for connectivity state checks, split test into two threads
* various cleanup
* rename Core to Unsafe for emphasis, clean up tests more
* add requested comment
* remove slice_unref binding, use sliceFree when converting buffer to bytestring
