Make the CLI more Unix-friendly

[Nachasic]

Thank you for this incredible tool!

I've tried using it for my math study workflow, where I need to transcribe lots of math from textbooks, websites and handwritten notes. A specific workflow I had in mind:

1. Grab a screenshot of a sceen area;
2. Feed the screenshot to LaTeX-OCR;
3. Grab the LaTeX prediction from stdout and pipe it into my clipboard.

Unfortunately, the CLI turned out to be barely usable for me: when calling pix2tex --file pic.png the utility shows the interactive TUI instead of processing the file right away, so I came up with two changes to fix this:

1. Remove checks for arguments.gnome from main (my python env was complaining about gnome being absent from the arguments namespace);
2. Remove interactive TUI from the CLI

You can see the resulting workflow on this gif:

The bash script I'm using:

#!/usr/bin/bash

# Create a temporary directory
TEMP_DIR=$(mktemp -d) 

# Grab an area screenshot and save it to temp folder
flameshot gui --path $TEMP_DIR/pic.png

# Feed the screenshot to pix2tex and pipe the prediction to clipboard
pix2tex --file $TEMP_DIR/pic.png | xclip -sel clip

# pix2tex takes a couple seconds to process, notify me when done
notify-send "GrabTeX" "TeX is copied to clipboard"

# Remove the temporary directory
rm -rf $TEMP_DIR

I would love to make a contribution that enables this kind of workflow for anybody, but I'm pretty new to Python development. Please let me know if there is anything else I should do in this PR in order for it to get merged.

[Nachasic]

Closing in favor of #187