added instructions on how to add this library

svn: r7333

collects/teachpack/htdc/Docs/colors.thtml

@@ -1,7 +1,15 @@
 { (define LIBNAME "A Colors Library (HtDC)")
   (include "head.tinc") }
 
-This <code>draw</code> package provides classes for representing colors: 
+<p>Add 
+<pre><code>
+  import colors.*
+</code></pre>
+at the top of your Definitions Window to import this library. 
+</p>
+
+
+<p>This <code>draw</code> package provides classes for representing colors: 
 <pre>
 <code>
                               +--------+
@@ -18,6 +26,7 @@ This <code>draw</code> package provides classes for representing colors:
          +-------+  +-------+ +-------+ +-------+ +-------+  +-------+ 
 </code>
 </pre>
+</p>
 
 <p>The <code>AColor</code> class is abstract. Its variants (subclasses) are
 created with no arguments. 

collects/teachpack/htdc/Docs/draw.thtml

@@ -1,6 +1,14 @@
 { (define LIBNAME "A Functional Drawing Library (HtDC)")
   (include "head.tinc") }
 
+<p>Add 
+<pre><code>
+  import draw.*
+</code></pre>
+at the top of your Definitions Window to import this library. 
+</p>
+
+<p>
 This <code>draw</code> package provides classes and methods for a visual
 world. Here is its class diagram of public fields and methods: 
 <pre>
@@ -24,6 +32,7 @@ import geometry.*;
  +-----------------------------------+       +---------------------------------------+
 </code>
 </pre>
+<p>
 
 <a name="world" />
 <p>The abstract <code>World</code> class exports the following methods: 

collects/teachpack/htdc/Docs/geometry.thtml

@@ -1,7 +1,14 @@
 { (define LIBNAME "A Geometry Library (HtDC)")
   (include "head.tinc") }
 
-This <code>geometry</code> package provides a class for representing
+<p>Add 
+<pre><code>
+  import geometry.*
+</code></pre>
+at the top of your Definitions Window to import this library. 
+</p>
+
+<p>This <code>geometry</code> package provides a class for representing
 positions in a Cartesian world:
 <pre>
 <code>
@@ -13,6 +20,7 @@ positions in a Cartesian world:
                       +----------+
 </code>
 </pre>
+</p>
 
 <p>To create an instance of the <code>Posn</code> class, a program must supply
 two <code>int</code> values: one for its x coordinate of the canvas and the

collects/teachpack/htdc/Docs/idraw.thtml

@@ -2,7 +2,14 @@
   (include "head.tinc") }
 
 
-This <code>idraw</code> package provides stateful classes and imperative methods
+<p>Add 
+<pre><code>
+  import idraw.*
+</code></pre>
+at the top of your Definitions Window to import this library. 
+</p>
+
+<p>This <code>idraw</code> package provides stateful classes and imperative methods
 for a visual world. Here is its class diagram of public fields and methods:
 
 <pre>
@@ -26,6 +33,7 @@ import geometry.*;
                                             +------------------------------------+
 </code>
 </pre>
+</p>
 
 <p>The abstract <code>World</code> class in <code>idraw</code> provides the same
 methods as the <code>World</code> class in <a href="./draw.html#world">the