feat: Leading and trailing edge debounce for the file watch

[Mike-Dax]

This PR removes the 100ms wait before starting compilation of changed files and instead introduces a leading+trailing edge debounce + an md5 hash.

The previous behavior was to wait until the 100ms after the last time the user saved a file, then it would compile.

Now it will immediately compile upon first save, and if the file is saved again it will debounce in a similar manner to previously. It will also hash the file and check if it has changed since the last compile. The debounce has been increased to 300ms.

[PepsRyuu]

Hmmm. Will need to test this one out a bit. There was a few situations I've been trying to address with the delay, and it was the quickest hack I could think of:

• Sometimes when starting for the first time, hundreds of change events trigger, and it will rebuild hundreds of times and eventually start running.

• Multiple events can trigger for the one file on a single save and might throw distinct events.

• If multiple files are saved at the same time (for example, find and replace), could trigger multiple builds.

Might take a bit longer to get back to you on this one!