Terminate the program if a build fails

[mitar]

Currently the program is left running, so if the build fails, you have an old version of the program running. It happened to me multiple times that I tried to use the HTTP app and it looked like working, but then there was no expected change in its behavior. Only then I realized that the new code didn't compile. It would be better if the program would be terminated always (after the build, if it is successful a new version is stared, otherwise nothing is started) so that I would see errors when browser tries to connect to a new version.

At least provide a flag to enable this behavior.