Fix get command on macOS

[kkga]

fixes #10

Additionally, the get command:

• now has an -R flag to print out raw Kakoune-quoted output
• prints Kakoune's errors to stderr

[kkga]

@TeddyDD Hey 👋

I had to make a few changes in order to fix the hanging issues in kak.Get() on macOS.

Problem I isolated, in short: the fsnotify doesn't trigger a WRITE event if the file content is empty after update, so I came up with an ugly solution to always prefix Kakoune's echo output with an arbitrary string that gets trimmed later (b2f27e9).

I also added a few more enhancements along the way:

• the get command now has an -R flag to print out Kakoune-quoted output directly
• if Kakoune errors-out, the error is written to stderr f9f5fb4

If you a have any desire and/or some free time, I'd appreciate if you could briefly test this to make sure all works :) Thanks!

[TeddyDD]

Sure!

[TeddyDD]

It seems to be working as expected on Linux.

[kkga]

Awesome, glad it works for you.

I'm gonna test-drive this for a few more days before merging.

Thank you.

[TeddyDD]

Okay, I'll be running this branch as well, let you know if something explodes.