Version 1.1.1: Undo button fixed and functional, and README.md update

Undo button functionality for all task stages, including finished tasks and the repeat cycle.

- version 1.1.1
- link to changelog, on the wiki, in the README
- included a .gitignore file to prevent go_definitions.php from being committed
- added a default of '0' for the count variable in the wp_go table