Bumped version to 0.2.0; docs edits.

I've added cond and cmp to the library so that should bump the minor
version no. I think.

docs/Ordered_Binary_Trees.ipynb

@@ -386,7 +386,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "#### Now we can define `Tree-add`\n",
+    "### Now we can define `Tree-add`\n",
     "    Tree-add == [popop not] [[pop] dipd Tree-new] [] [[P >] [T] [E] ifte] genrec\n",
     "\n",
     "Putting it all together:\n",
@@ -415,7 +415,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "#### Examples"
+    "### Examples"
    ]
   },
   {
@@ -751,7 +751,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "### Processing the current node.\n",
+    "#### Processing the current node.\n",
     "\n",
     "`R0` is almost certainly going to use `dup` to make a copy of the node and then `dip` on some function to process the copy with it:\n",
     "\n",
@@ -771,7 +771,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "### Recur\n",
+    "#### Recur\n",
     "Now `R1` needs to apply `[Tree-iter]` to `left` and `right`.  If we drop the key and value from the node using `rest` twice we are left with an interesting situation:\n",
     "\n",
     "    key [key value left right] [Tree-iter] R1\n",
@@ -829,7 +829,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## `Tree-iter`\n",
+    "### `Tree-iter`\n",
     "\n",
     "    Tree-iter == [not] [pop] roll< [dupdip rest rest] cons [step] genrec"
    ]
@@ -847,7 +847,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "#### Examples"
+    "### Examples"
    ]
   },
   {
@@ -1011,7 +1011,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "#### Process the left child.\n",
+    "### Process the left child.\n",
     "Staring at this for a bit suggests `dup third` to start:\n",
     "\n",
     "    [key value left right] R0        [Tree-iter-order] R1\n",
@@ -1035,7 +1035,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "#### Process the current node.\n",
+    "### Process the current node.\n",
     "So far, so good.  Now we need to process the current node's values:\n",
     "\n",
     "    left Tree-iter-order [key value left right] [Tree-iter-order] [[F] dupdip] dip\n",
@@ -1052,7 +1052,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "#### Process the right child.\n",
+    "### Process the right child.\n",
     "First ditch the rest of the node and get the right child:\n",
     "\n",
     "    left Tree-iter-order key [key value left right] [Tree-iter-order] [rest rest rest first] dip\n",
@@ -1068,7 +1068,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "#### Defining `Tree-iter-order`\n",
+    "### Defining `Tree-iter-order`\n",
     "The result is a little awkward:\n",
     "\n",
     "    R1 == [cons dip] dupdip [[F] dupdip] dip [rest rest rest first] dip i\n",
@@ -1163,7 +1163,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "#### The base case `[]`\n",
+    "### The base case `[]`\n",
     "As before, the stopping predicate just has to detect the empty list:\n",
     "\n",
     "    Tree-get == [pop not] [E] [R0] [R1] genrec\n",
@@ -1186,7 +1186,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "#### Node case `[key value left right]`\n",
+    "### Node case `[key value left right]`\n",
     "Now we need to figure out `R0` and `R1`: \n",
     "\n",
     "    [key value left right] key R0 [BTree-get] R1\n",
@@ -1200,7 +1200,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "#### Predicate:\n",
+    "#### Predicate\n",
     "\n",
     "    P == over [get-node-key] nullary\n",
     "    get-node-key == pop popop first\n",
@@ -1386,7 +1386,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "# Tree-delete\n",
+    "## Tree-delete\n",
     "\n",
     "Now let's write a function that can return a tree datastructure with a key, value pair deleted:\n",
     "\n",