"auto flush" tty optionally

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)

首先比較 auto-flush 分支與目前的 libpython-clj 實作，並檢視 #216 的修正。定義應如何設定 autoflush，並透過一個使用第三方 Python 函式庫進行寫入的長時間執行程序加以驗證；啟用此選項後能可靠地在每次寫入時執行 flush，即表示完成。