Added head, tail, init, last
Moved fold functions into func/list/fold
Added intersperse command.

Given an element and a list, intersperse the element inside the list.

For example

  a = 'abcde';
  intersperse(',', a)

  ans =

  a,b,c,d,e
Added subsequence command.

This works for creating subsequences for lists smaller than 15 elements.

This also works on both lists and character arrays.
Added initialisation comment for subsequences.
Added help for subsequences.
Added concatMap.
Merge branch 'feature/list_funcs' into develop.

Contains initial list functions.