Replace INIT macros with init functions in src/lib/kinetic_types_internal.c.

This is in preparation for changing the HMAC auth initialization, to
also allow pinOp-based authentication.
Initial version of messaging bus
Track incremental writes in echo server.
Extract constants for backpressure coefficients.
Switch to using shared read buffer for whole listener thread.
Add Seagate copyright header to threadpool and message bus source.
Add hash table to track active file descriptors, tune backpressure..
Update tests / types for API changes.
Import threadpool library
Fix numeric types for IDs.
Include stdint.h for uintptr_t.
Register socket99 as dependency that must be built before test_internals
Makefile and warning cleanup
Integration: Eliminate init of fields that are no longer present.
Add error handler callback for unpacked, invalid user messages.
Update integration of internal static libraries, build process in Makefile
Fix warnings related to unused vars and signed/unsigned comparisons.
Rework Makefile: put all .o in objs/ , not use multiple static libraries.
Merged in develop
Merged thread pool 'bus' branch into admin_api branch. Disabled a KineticClient_Flush() test in system_test_flush until issue with PUT is resolved.