- add doc index

git-svn-id: http://root.cern.ch/svn/root/trunk@21446 27541ba8-7e3a-0410-8455-c3a389f83636

histpainter/doc/index.txt

+This directory contains all the basic histogram painting classes.
+BEGIN_HTML
+ See:
+<ul>
+<li><a href="ftp://root.cern.ch/root/doc/4Graphs.pdf">The Chapter about the Graph classes in the Users Guide.
+</a></li>
+<li><a href="ftp://root.cern.ch/root/doc/3Histograms.pdf">The Chapter about the Histogram classes in the Users Guide.
+</a></li>
+<li><a href="http://root.cern.ch/root/htmldoc/examples/graph.C.html">Using and drawing a simple TGraph.
+</a></li>
+<li><a href="http://root.cern.ch/root/htmldoc/examples/graph2derrorsfit.C.html">TGraph2D with errors drawing.
+</a></li>
+<li><a href="http://root.cern.ch/root/htmldoc/examples/h1draw.C.html">Drawing Options for 1D Histograms.
+</a></li>
+<li><a href="http://root.cern.ch/root/htmldoc/examples/hbars.C.html">Demo of option bar with histograms
+</a></li>
+<li><a href="http://root.cern.ch/root/htmldoc/examples/hsimple.C.html">Simple drawing of a 1D Histograms.
+</a></li>
+<li><a href="http://root.cern.ch/root/htmldoc/examples/hsum.C.html">Filling several histograms and some graphics options.
+</a></li>
+<li><a href="http://root.cern.ch/root/htmldoc/examples/surfaces.C.html">Drawing a TH2 as a 2-D surface.
+</a></li>
+<li><a href="http://root.cern.ch/root/HowtoDraw.html">How to Draw objects.
+</a></li>
+</ul>
+END_HTML