Switch to parsing detailed network stats with native code, which
is 71% faster than ProcFileReader.
Change-Id: I2525aaee74d227ce187ba3a74dd08a2b06514deb
Deprecate transport layer statistics, leaving only the summarized
network layer statistics.
Improve documentation to be clear about layers where measurements
occur, and their behavior since boot. Under the hood, move to using
xt_qtaguid UID statistics.
Bug: 6818637, 7013662
Change-Id: I9f26992e5fcdebd88c671e5765bd91229e7b0016