main : don't print special tokens with --grammar (#6923)

main : don't print special tokens with --grammar (#6923)

* main : don't print special tokens with --grammar

The CLI interface was recently changed to print special control tokens
like the </s> stop message one. This token shouldn't be printed if the
grammar flag was passed, unless the grammar specifies it, because that
breaks shell-scriptability.

* main: use seperate stream for control characters

* main: use dprintf and add --ctrl-token-no-out and --ctrl-token-fd-out

* main: dprintf isn't part of the IEEE POSIX standard. Just use write().

* main: remove --ctrl-token-fd-out in favor for fcntl() based detection

* common.cpp: accidentally removed --interactive-first

* main: only merge stdout and control token if not in conversation or grammar mode

* main: rejig control token descriptor handling

* main: must check pipe status on very top of program

* main: renamed --no-special from  --ctrl-token-no-out and other refactoring

* main: refactor ctrl_token_no_out --> no_special

* llama: rename llama_token_is_control_token() to llama_token_is_control()

* main: remove special token file descriptor feature (#5)

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Co-authored-by: Brian <redacted>