In-editor Isaac launcher + log awareness

This update introduces features meant to accelerate development and test cycle, here is a quick glance on what is new:

• Quick Isaac launch command using f6 (the key can be rebound in your keymap.cson, if you modify the Atom-boilua:launch-game command).
• When the game is launched, Atom-boilua starts listening the the isaac log.txt file and reacts to errors thrown in the folder.
  • If an error occurs, it will focus on the editor, at the file where the error occurred, at the correct line.
  • This is only true if the mod that has thrown the error is the same as the one you currently are working on. Otherwise, the editor do NOT take focus, you are only given the option to do so.
• You can add custom commands to run when launching the game. For example, I use this to launch beside the game a windows showing the content of the log.txt.