Change filename to be a positional argument

[Ben1152000]

This PR contains the following changes:

• Change filename to a positional argument (sootty filename.vcd instead of sootty -f filename.vcd)
• Replace -d display argument with -o output (which does the opposite)
• Fix minor bugs/clean up code in save.py

[KarthikL1729]

Looks good to me, fixed a small bug in the reloading part, functionality wise it's perfect. Also really like the new dict representation in the save file!

However I do think the old date format would be preferred for most usecases?

I also think providing absolute path would be better as that would allow us to reload from anywhere in the directory tree, will push a fix for that.

[KarthikL1729]

Pushed the fix and tested functionality, would like your opinion on the date format!

[Ben1152000]

However I do think the old date format would be preferred for most usecases?

I went with the unix timestamp since it's very easy to compare two values. I'm not sure if there are any weird issues when comparing dates, but if you think it's better to have readability feel free to change it.

I also think providing absolute path would be better as that would allow us to reload from anywhere in the directory tree, will push a fix for that.

Agreed, this behavior seems more reasonable.

[KarthikL1729]

However I do think the old date format would be preferred for most usecases?

I went with the unix timestamp since it's very easy to compare two values. I'm not sure if there are any weird issues when comparing dates, but if you think it's better to have readability feel free to change it.

I also think providing absolute path would be better as that would allow us to reload from anywhere in the directory tree, will push a fix for that.

Agreed, this behavior seems more reasonable.

I think the unix timestamp is fine as well, not an issue per se. Will solve conflicts and approve.