The previously used minification libraries were:
a) Unmaintained
b) Had some silly licensing issues (MDL-36457)
The new library is smaller, maintained, active and GPL-compatible.
When minifiying JS, unnecessary semi-colons are removed - this includes the
trailing semi-colon.
Since we join multiple files together after minification, we need to add an
additional semi-colon in this situation to produce valid JavaScript.