misc doc fixes and organization

beziers reorg
arc bug fix for endpoint=false and N=undef

lists.scad

@@ -387,6 +387,7 @@ function repeat(val, n, i=0) =
 //   s = The starting value of the list of numbers.
 //   step = The amount to increment successive numbers in the list.
 //   reverse = Reverse the list.  Default: false.
+// See Also: idx()
 // Example:
 //   nl1 = count(5);  // Returns: [0,1,2,3,4]
 //   nl2 = count(5,3);  // Returns: [3,4,5,6,7]
@@ -851,9 +852,10 @@ function idx(list, s=0, e=-1, step=1) =
 // Topics: List Handling, Iteration
 // See Also: idx(), triplet(), combinations(), permutations()
 // Description:
-//   Takes a list, and returns a list of adjacent pairs from it, optionally wrapping back to the front.
+//   Returns a list of all of the pairs of adjacent items from a list, optionally wrapping back to the front.  The pairs overlap, and
+//   are returned in order starting with the first two entries in the list.  If the list has less than two elements, the empty list is returned. 
 // Arguments:
-//   list = The list to iterate.
+//   list = The list to use for making pairs
 //   wrap = If true, wrap back to the start from the end.  ie: return the last and first items as the last pair.  Default: false
 // Example(2D): Does NOT wrap from end to start,
 //   for (p = pair(circle(d=40, $fn=12)))
@@ -883,7 +885,7 @@ function pair(list, wrap=false) =
 // Topics: List Handling, Iteration
 // See Also: idx(), pair(), combinations(), permutations()
 // Description:
-//   Takes a list, and returns a list of adjacent triplets from it, optionally wrapping back to the front.
+//   Returns a list of all adjacent triplets from a list, optionally wrapping back to the front.
 //   If you set `wrap` to true then the first triplet is the one centered on the first list element, so it includes
 //   the last element and the first two elements.  If the list has fewer than three elements then the empty list is returned.
 // Arguments: