"auto flush" tty optionally #270

The fix of #216 is not fully solving the issue.

using "libpythin-clj", there is so far no way to enforce "autoflush".
So when a third party python library does not explicitly flush, then we cannot force it.
And this can result in not seeing "debug outputs" on time for long running processes.
(in my tests they only came when the JVM proccess ends)

When using a normal "python" executable, there are some documented ways, but none of it is working with "libpython-clj".
(using "unbuffer" and similar tricks, like env varaibales: PYTHONUNBUFFERED=false)

On this branch https://github.com/behrica/libpython-clj/tree/auto-flush
I have a solution (so far hardcoded), which solves it.
It adds "flush" to each write.

This would need to be optional and configurable (eventually together with a way to configure as well the return value of "isatty" (which I did not need in my tests, false was working fine)