liblog: document the liblog<->logd protocol format

This protocol documentation is spread out among various functions
where it is implemented.  This change makes a single
README.protocol.md file with a high level overview, referencing the
struct names where useful.

Test: n/a
Change-Id: I83c9f484352b489b4a20cce241d92413f780f9ec
2 files changed
tree: 94e66058b956978d71629538922f76112d362ed2
  1. liblog/
  2. logcat/
  3. logd/
  4. logwrapper/