livereload task improvements

[mirekdlugosz]

• use custom build command, with caching turned on - this reduces site build time by around 40% on my testing machines
• collect all glob patterns in a list and then call server.watch on each item - this allows to have single place where callback function must be specified
• use '**/*.html' as glob in template, to track changes in subdirectories (some themes include "partials" directory, where they store common widgets used in few different templates)

[justinmayer]

Thanks for the submission, Mirek. There seem to be some interesting changes in here. Have you seen any instances in which caching interfered with normal development? (e.g., stale results due to improper cache invalidation, etc.)

[mirekdlugosz]

Have you seen any instances in which caching interfered with normal development? (e.g., stale results due to improper cache invalidation, etc.)

So far I have not encountered any problems with caching. I tried changing stylesheet and jinja template file, and I edited one article, all while this task was running. That's not much, but I have been using this only for few days.

I guess one's mileage may vary depending on installed plugins and what exactly they do. Also, I clean up cache directory after liveserver task, so I have easy and fast way of starting with known state. I can add something similar here, if you feel that would be worthwhile.

[justinmayer]

My limited testing yielded no problems, so I think we can merge and address any issues as they arise.

Many thanks for the useful enhancement, Mirek! 🥇