kpm ignores errors of project.json event scripts

[cherrydev]

If you set, for example, a "prebuild" script in project.json, and the command fails (returns a non-zero exit code) kpm completely ignores it. Likewise, if a "postbuild" script fails, "kpm build" still reports "Build Succeeded".

...
"scripts": {
        "prebuild": "foo"
    }
...

and then run > kpm build you will receive the message

'foo' is not recognized as an internal or external command,
operable program or batch file.

The remainder of the build will then continue. I've yet to think of reason why this would be the desired behaviour.
Running KRE-CLR-x86.1.0.0-beta1

[Praburaj]

Fixed #1016