Allow users to specify the browser in which to open the plan files

[PaulRBerg]

I use different browsers on my machine for different purposes.

It would be helpful to have the ability to set an explicit browser in which the plans are opened by Plannotator, instead of using the default browser.

[backnotprop]

This will be available in the next release via the PLANNOTATOR_BROWSER environment variable.

Usage:

# macOS - app name or path
export PLANNOTATOR_BROWSER="Google Chrome"
export PLANNOTATOR_BROWSER="/Applications/Firefox.app"

# Linux/Windows - executable path
export PLANNOTATOR_BROWSER="/usr/bin/firefox"

If not set, Plannotator continues to use your system default browser.

PR: #48

[backnotprop]

Published in release v0.4.15

[PaulRBerg]

nice, thx for the quick update