Filesystem watcher

watcher.[bat,sh] runs the advance compiler (using your settings set in setup.[bat,sh]) on filesystem changes. If the compiler is already running it restarts it. Saves its output to FC_pregmod.watcher.html.

I have double and triple checked that the changes made don't break anything (especially the changes to gulpfile.js).

Added npm run watch.

This should be ready for merging.

changed the description

mentioned in issue #5069 (closed)

mentioned in issue #5013

mentioned in commit 3eaca8fb

merged