Switch default behavior to be more unobtrusive

It strikes me as a bad thing to have the keyword expansion and file permission changing turned on by default.  When I open a text editor, I don't expect it to silently change the permissions on a file.  Similarly, when I type a comment using a word like "var" or "comma", or use an "=" in a string inserted into a config file, it's quite surprising to have those words be automatically changed.

Therefore, I propose that the functionality be switched to include that functionality, but require the end-user to turn it on if they want silent changes.