Began solution to #442

The count function currently has a bug, but this is easily fixed by simply
following the correct algorithm.
Fixed coin_count and wrote coin_list functions

The coin_count function now works correctly.  I wrote a draft of coin_list,
although it is buggy.  It does not correctly group coins in sub-lists.
Fixed bug in coin_list

Coins were not being appended to all items of the list.  This bug has been
fixed and the functions now work correctly.
Moved coin change to correct directory

Also updated the index.