Renamed StripWhiteSpace -> StripWhitespace to match an upstream change.
Added accessors for gjstest.Matcher descriptions.

Deprecated the plain string properties. This is part of a change arc
that will end in expectThat, expectCall, and the built-in matchers not
computing descriptions unless a failure occurs. The motivation is to
avoid calling gjstest.stringify when unnecessary, because this can be
expensive for very large objects.

Future changes will remove all uses of the deprecated string properties,
then remove them altogether.
Add a convenient link to re run a single test.

Add a convenient link to re run a single test case at the top of each case's log.
Changed wording for the re-run link.
Eliminated deprecated properties on gjstest.Matcher.

Updated all uses within gjstest to instead call the new accessors.
Added notes about toString and slowness to gjstest.stringify.
Added the ability to lazily specify matcher descriptions.
Made equals and recursivelyEquals lazy in computing descriptions.
Made mock expectation matching lazy in computing descriptions.
Merge branch 'google'