js2-mode is no longer developed and we recommend js-mode these days,
so switch the modelines to specify that, and make them consistent
across all files.
https://bugzilla.gnome.org/show_bug.cgi?id=660358
Sometimes it is useful to print numbers in hex format - add the
appropriate specifier. Also support a minimum field width to
pad the formatted string with spaces (or zeros if the width is
prefixed with '0').
https://bugzilla.gnome.org/show_bug.cgi?id=622597
Add String formatting by extending the String object with a
format method.
Now we can do stuff like "Text: %s, %d".format(somevar, 5)
This is required for proper translation of some strings.
https://bugzilla.gnome.org/show_bug.cgi?id=595661
