Add docs for SkMatrix, SkRect, SkIRect, SkBitmap

Also minor changes to earlier docs.

Many small changes to improve indentation in generated includes.
Added support for matrix math illustrations.

Docs-Preview: https://skia.org/?cl=58500
Bug: skia:6898
Change-Id: I7da58ad55f82d7fd41d19288beb2cd71730fb01f
Reviewed-on: https://skia-review.googlesource.com/58500
Commit-Queue: Cary Clark <caryclark@skia.org>
Reviewed-by: Cary Clark <caryclark@google.com>
Reviewed-by: Cary Clark <caryclark@skia.org>
diff --git a/docs/undocumented.bmh b/docs/undocumented.bmh
index 0239034..8a57459 100644
--- a/docs/undocumented.bmh
+++ b/docs/undocumented.bmh
@@ -11,7 +11,7 @@
  PDF XPS
  RFC
  NaN NaNs
- Bezier Coons Cartesian
+ Bezier Coons Cartesian Euclidean
  C C++ Destructor Subclasses
  SaveLayerFlags # not external; need to add typedef support
  SkUserConfig  # not external, but still thinking about how markup refers to this
@@ -336,6 +336,8 @@
             ##
             #Method size_t computeByteSize(size_t rowBytes) const
             ##
+            #Method void validate() const
+            ##
         ## 
     #Subtopic ##
     #Class SkImage
@@ -362,6 +364,11 @@
 #Topic Image_Scaling
 ##
 
+#Topic ISize
+#Struct SkISize
+##
+##
+
 #Topic Left_Side_Bearing 
 ##
 
@@ -559,6 +566,11 @@
     #Subtopic ##
 #Topic ##
 
+#Topic Point3
+#Struct SkPoint3
+##
+#Topic ##
+
 #Topic PostScript
 #Substitute PostScript
 #Subtopic Arct
@@ -637,7 +649,8 @@
 #Topic ##
 
 #Topic Size
-#Alias ISize
+#Struct SkSize
+##
 ##
 
 #Topic Sprite
@@ -645,7 +658,7 @@
 #Topic ##
 
 #Topic Stream
-#Class SkFlattenable
+#Class SkStream
 #Class ##
 #Topic ##
 
@@ -702,6 +715,7 @@
 ##
 
 #Topic Vector
+#Alias Vectors
 #Struct SkVector
 ##
 ##