builder.CompletionStatus and vbld_BuildDone()

[kinook]

A couple problems with this:
1) The file loggers are currently disposed of before the vbld_BuildDone script event fires.
2) When the build is canceled, if the vbld_BuildDone event takes very long to run, it will be aborted (to handle the situation of a build being aborted while script code is executing, but it should wait for this particular event to finish).

We'll investigate explicitly supporting this in the future (there's also a request to support building failure steps if the build is canceled, which would provide another way to achieve this).

For now, you might try shortening the event script code (maybe just call Builder.RunProgram to invoke a pre-defined send mail project, passing dynamic parameters on the command-line).