lookingGlass: Fix newline replacing

text.replace() returns the new string as strings in JS are immutable.
Bind "this" for various methods

For extremely silly reasons with how the class framework works, the wrapper
method requires "this" to be bound in order for it to work, or else we'll
emit errors in strict mode.

https://bugzilla.gnome.org/show_bug.cgi?id=707892