Ignore updates to source files while live-reloading is in progress

[damithc]

Current: if source files are updated while a live-reload is in progress, there is high chance that the live-reload will crash out. IDEs do auto-saves of files at unpredictable times, which makes this problem particularly bad.

Suggested: Either queue (or at least ignore) any trigger to live-reload while there is an active live-reload.

[damithc]

Seems live reloading gets triggered by IDE temp files e.g., \text.md___jb_tmp___. Given that temp files are named in a certain style., may be possible to ignore those?

[damithc]

In fact, I suspect ignoring these temp files altogether can reduce the crash frequency during live reloading. It seems these files appear/disappear fast and can interfere with the rebuild process.