adding upgrade notes

readme.txt

@@ -1,3 +1,18 @@
+Upgrade Notes
+-------------
+
+Upgrading from 1.x to 2.0
+
+I suggest removing SVG 1.0 from the python installation.  This involves removing the SVG directory (or svg_chart*) from site-packages.
+
+Change import statements to import from the new namespace.
+
+from SVG import Bar
+Bar.VerticalBar(...)
+becomes
+from svg.charts.bar import VerticalBar
+VerticalBar(...)
+
 --- Still to do ---
 
 -  Factor out default stylesheets so that individual properties may be overridden without copying the entire stylesheet into another app.