The OpenEmbedded build infrastructure now has a fairly sane event
handling core.  The following are the events which get fired at
appropriate points during the build process:

TaskStarted:
TaskFailed:
TaskSucceeded:

	The task status event classes have a 'task' attribute, which is
simply a string containing the task to which this event applies.  They also
have a 'data' attribute, which contains the environment data of the package
in question.

PkgStarted:
PkgSucceeded:
PkgFailed:

	The package build status event classes are a bit higher level.  That
is, they reflect the overall build status of a given package as a whole, without
the task level breakdown.  The 'package' attribute is a string which contains
the package which failed, in the usual form (i.e. content/glibc-2.3.1-r0).


TODO:
UnsatisfiedDep
RecursiveDep
MultipleProviders

Add 'log' data to the task and package builds, which contains the stdout and
stderr of the task/package which succeeded/failed, so that email notifications
of failures can include the build log.