Revert "Renamed partial() to insertEl() and changed it to append the inner element if no match is found"

This reverts commit 5e47a5f9e220958b90295a53b8fac1c9a5848175.
Revert "partial() utility method for applying an inner view to an outer view"

This reverts commit 987d243a40aaab5d7b51462abfd40ae6cdeab9b8.