Saprate Variables into its own file

[Andonome]

Searching for variables, then committing them to the right branch can be a chore. I've separated out the local variables into its own file, called 'vars.tex'.

Changes to this file should be ignored, so the file initially presents as example-vars.tex, and the Makefile then makes vars.tex (which is in the .gitignore).

tl;dr: run

make && $EDITOR vars.tex

[mkropat]

Thanks for sharing the improvement!

Personally I like all the variables and content in one file, but I don't feel strongly about it—especially since it's only the example code so everyone can use it the way they want.

How about this: if someone else posts on this PR that they like the change, and no one objects in the meanwhile, I will happily merge this change.

[Andonome]

No worries either way. I've been playing with the repo, and thought I'd share my mods.

I spent a bit of time trying to add Maths support for the grand total, but it's a lot harder than it looks, so I don't think I'll be adding that PR.

[mhalano]

Hello, I like to use a separate file because I can process easier the variables using a shell script. Some parts will be set in stone, basically, like my business name, but others, like the invoice value, will variate a lot, and in this case, would be nicer to have a smaller file to process.