commit ab8dc21743e85d281c81521e794485f4962256ef
author Todd Wang <toddw@google.com> Mon Oct 19 16:52:53 2015 -0700
committer Todd Wang <toddw@google.com> Mon Oct 19 16:52:53 2015 -0700
tree bb180526e39d0b9cc06739d3f79a86f2d1ca0d22
parent c91e8285bd0aa33588a938318982ec11ea696c2a

ref: Added v.io/x/lib/timing package.

Adds the timing package, which provides utilities for collecting
trees of timing information and dumping it with a nice format.
An example of the output format:

00:00:01.000 root       98.000s       00:01:39.000
00:00:01.000    *           9.000s    00:00:10.000
00:00:10.000    foo        45.000s    00:00:55.000
00:00:10.000       *           5.000s 00:00:15.000
00:00:15.000       foo1       22.000s 00:00:37.000
00:00:37.000       foo2       18.000s 00:00:55.000
00:00:55.000    bar        25.000s    00:01:20.000
00:01:20.000    baz        19.000s    00:01:39.000

Also add this support to the cmdline package via the -time flag,
and add some preliminary timings for "jiri update".

MultiPart: 4/4

Change-Id: If221e22d2cdd54e47f4280d0e230b107f34123e5