Allow arguments when using BP_DIRECT_PROCESS

[c0d1ngm0nk3y]

When using BP_DIRECT_PROCESS because you do not have a bash, the buildpack must tokenize the command string in case on arguments.

Summary

In this case, do the same as for the tiny stacks.

Use Cases

In case the process you wanna start has some arguments.

Checklist

• I have viewed, signed, and submitted the Contributor License Agreement.
• I have linked issue(s) that this PR should close using keywords or the Github UI (See docs)
• I have added an integration test, if necessary.
• I have reviewed the styleguide for guidance on my code quality.
• I'm happy with the commit history on this PR (I have rebased/squashed as needed).

[dmikusa]

Good catch, thanks for the PR