Allow output to non-tty STDOUT

[VarunKoyyalagunta]

I want to run rmem in a scripted batch mode, by creating a file containing a list of commands and be able to do something like this -

cat file.cmd | ./rmem ... | tee log

(It's more complicated by the fact that I'm running the ./rmem ... part inside a container, but that doesn't really matter)

If I compile with UI=headless, rmem accepts input from a STDIN pipe. However I can't redirect STDOUT. I get the following error -

Output is not a terminal, '-interactive true' is not allowed.
  Use '-interactive false'

Removing the check, like so, achieves what I want -
VarunKoyyalagunta@8f0da61

I thought of creating some sort of -batch switch instead to override the check, but I'm not sure how useful the check is to begin with and removing it seemed easier.

If the above change is okay, I can create a PR. Or, if you prefer an additional switch like -batch, I can code that.