configure location of PHPUnit executable using humbug.json(.dist)

[domnikl]

In my scenario, I rename the phpunit.phar to e.g. phpunit-4.8.3.phar in my project. But that means that humbug can't find it automatically. What about a possibility to add the exact location to the config like this:

{
    "source": {
        "directories": [
            "src"
        ]
    },
    ...
    "phpunit": {
        "phar": "build/phpunit-4.8.3.phar"
    }
}

[daniel-mueller]

This would be a really great feature to have. I'm currently in a similar situation and have to work around it in (at least in my opinion) unnecessary complex ways during my build process. Being able to optionally define the name of the phpunit.phar would be a great simplification for me.

[padraic]

Closing as merged in #155. Some changes proposed via #253.