This FORCEBUILD file should be deleted by Dart scripts to force Dart
to do a continuous build even if no other file in the repository has
been changed.  The idea is to fool Dart into thinking a file has been
changed so it will compile and submit.  This should be done when some
dependency of the build changes.  It is also helpful for triggering a
new continuous build when it is first started up.  Seeing that this
file has changed on the dashboard will make it apparent that the build
was started for reasons other than a file in the repository being
changed.
