minor improvements

[tvidal-net]

I am not sure if this project is still active, but since I am using a modified version of your tool, I thought it was just fair that I gave you the chance to merge these changes:

• Bump cargo-husky version to v1.5.0
• Add search by window id exclusively
• Print an error message when the window was not found instead of silently failing
• Return exit code 1 in case of errors to make it easier to use in shell scripts
• Accept negative index numbers so windowactivate %-1 activates the most recent window.

[einarpersson]

this looks like good additions! @jinliu could it be merged? is this project active? i hope so =)