Do not write options to config by default

[actuday6418]

This is really unusual to a user who

• Has iRust open in one window
• Edits config.toml in another window
• Closes and opens iRust
• Sees changes to config have reverted

Saving config changes should be an explicit command.

[sigmaSd]

Thanks for the feedback, that makes sense

fixed in 1.71.24 the new explicit command is save_options

[sigmaSd]

I ha to revert this because it interacted poorly with the options loading and the detection of first run of irust, I can it correctly when I have time