Change agent text encoding

Change the text encoding to be easier to parse off-line.  Also fixes the
per-thread sampling bias Hans pointed out yesterday.  Adds the python
script I use to uncompress the text encoding.

Bug: none
Test: attach the agent; run the startop test; uncompress; make flame graph; view
Change-Id: I4a882642e659d8512a02d4980c82fb52470ac7f9
3 files changed