Shrink code and prepare for the before() functions.
Wrote the before() functions.
Wrote the insertBefore() function.
(And added info documentation about the native version.)
Wrote the append() functions.
Implemented the appendTo() functions.
Forcing users to provide correct input for appending.
Wrote the prependWith() functions.
Improved documentation regarding ParentNodes.
Implemented the prependTo() functions.
Fixed bug in insertAfter().
Improved minification.