Collect build time to first task

[daithiocrualaoich]

Configuration and setup time is not captured since it does not constitute a build task. Investigate whether this can be captured by starting a clock in the TimingRecorder construction and recording it in buildTaskStarted if the timings list is empty.

[passy]

The best way to achieve this would be to compare the age of the process to the sum of all subtask timings. I'm afraid that this could be fairly difficult until Java 8 though when we get a proper Process API.

[passy]

Good example here where fetching plugins and dependencies take an insane amount of time of which we log nothing:

hartig@tw-mbp-phartig ~/P/t/someproject (undefined ▼ ▲ ) $ i@  () $ ./gradlew
Relying on packaging to define the extension of the main artifact has been deprecated and is scheduled to be removed in Gradle 2.0
flavor: custom
flavor: default
flavor: dogfood
flavor: nightly
:help

Welcome to Gradle 1.11.

To run a build, run gradlew <task> ...

To see a list of available tasks, run gradlew tasks

To see a list of command-line options, run gradlew --help

BUILD SUCCESSFUL

Total time: 4 mins 47.611 secs
== CSV Build Time Summary ==
Build time today: 0:00.008
Total build time: 13:52:27
(measured since 2 months ago)
== Build Time Summary ==