use colors package; log, logAll options; hook grunt errors

Switch from "bash-color" to "colors" package, which is the same package used by Grunt.  This insures that Grunt's --no-colors option works.

Added a "log" option, which specifies a callback for log messages to customize how the timing results are presented/stored.  This can be used, for example, to log build times in JUnit format for Jenkins integration.

Added a "logAll" option, which requests that ALL timings be logged, not just times over 2ms.

Hooked a couple more grunt functions, to insure timing results are also reported in error cases.