Compatible with mtr and possibly other tui programs

[zu1k]

This was previously discussed at #133, we still have some problems with mtr compatibility.

The following content is copied from #133 posted by @mzz2017 :

---

After the fix PR #132, we found that in different mtr display modes, nali still has exceptions.

To reproduce it, try:

> mtr baidu.com | nali
# and then press d to switch the display mode

At the beginning, we fixed it by scanning control runes (rune<0x20). Although it fixed the most problems, we found there was also some abnormal cursor jitter.

Finally, we think we shouldn't use bufio because it uses cache to delay reads. We should unblock as soon as the write finish on the other side of the pipe ends, and return the read result, process it and print it on the screen, which is what our PR does.

---

Currently we have the following problems:

• If we use io.Copy to replace bufio, there will be potential IP truncation and the IP will not be recognized.
  fix: we should not use bufio and to keep read and write behavior consistent #133 (comment)
  @mzz2017 mentioned that some kind of cache could be added to solve this.
  fix: we should not use bufio and to keep read and write behavior consistent #133 (comment)

• If we continue to use bufio, we may need to add additional control character scans to solve the cursor jitter problem in tui.
  fix: we should not use bufio and to keep read and write behavior consistent #133 (comment)

• Maybe we can add an arg like --mode tui to specifically be compatible with tui programs like mtr.
  fix: we should not use bufio and to keep read and write behavior consistent #133 (comment)

• The current scanning method is to splite text by \n and \r characters, but when encountering super-long input without newline characters, nali will freeze.
  fix: we should not use bufio and to keep read and write behavior consistent #133 (comment)

[mzz2017]

Additional info: We can see linux pipe size by command ulimit -a. By default, it is 8*512byte=4k.