Make temp directory configurable

[uliska]

Apart from generally being not nice to hard-code directory names making the ly_tmp directory configurable should be implemented to help #24. Purging the temp directory would not be possible if there are multiple .tex files in the original directory (which now share the temp directory).

[jperon]

Yes or not. One advantage of the sharing of a directory would be that, if two documents with same properties (width, size etc.) use the same score, it wouldn't get compiled two times. And we could write lists dependent on the name of the original .tex to let users choose which files they want to remove. I think it would be an argument againts the purge option, and to let users remove unnecessary files with their own commands.

That said, I agree that hard-code is generally a bad thing, and that letting users choose what they prefer is a good one. So we could add an optional argument to change the default tmp_ly, and a purge option ; users who don't want to use them won't have to change anything, those who want will be able to.

[uliska]

One advantage of the sharing of a directory would be that, if two documents with same properties (width, size etc.) use the same score, it wouldn't get compiled two times.

This is indeed a good argument. But of course I didn't want to suggest to have individual temp directories per document but the option to have them. I agree that the default use case would probably be to have one shared temp directory and leave all files as they are, doing the clean-up with some other tools and schedules.

Having the possibility to have a shared or individual temp directories will in any way add flexibility for users to create their workflows. And since there's a reasonable default they don't have to bother with it.