bookmaker initial checkin

bookmaker is a tool that generates documentation
backends from a canonical markup. Documentation for
bookmaker itself is evolving at docs/usingBookmaker.bmh,
which is visible online at skia.org/user/api/bmh_usingBookmaker

Change-Id: Ic76ddf29134895b5c2ebfbc84603e40ff08caf09
Reviewed-on: https://skia-review.googlesource.com/28000
Commit-Queue: Cary Clark <caryclark@google.com>
Reviewed-by: Cary Clark <caryclark@google.com>
diff --git a/docs/overview.bmh b/docs/overview.bmh
new file mode 100644
index 0000000..c6b0d1f
--- /dev/null
+++ b/docs/overview.bmh
@@ -0,0 +1,8 @@
+overview
+
+--------------------------------------------------------------------------------
+
+Skia draws 2D primitives, paths and bitmaps, using the styles in the SkPaint, to
+the device contained by the SkCanvas.
+
+--------------------------------------------------------------------------------