Generated code README and headers.

pkg/analyzer-experimental/README

Index: pkg/analyzer-experimental/README
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+This code is part of an experimental port of the Editor's analysis engine from
+Java to Dart. While we will continue to support the Java version of the analysis
+engine and the services built on it, we also intend to provide the same services
+to Dart-based applications. This is very early code and we expect it to change,
+possibly in significant ways. While we are eager to see other people make use
+of the analysis engine, we also want to be clear, in case you are interested in
+doing so, that the current API's should in no way be considered to be stable.
+
+In particular, this code was automatically translated from the Java
+implementation. The Java implementation that was translated is still under
+development and will continue to change over time. The translator that was used
+is still under development and the output produced by the translator will change
+over time. Therefore, the API presented by this code will change. In addition,
+any edits made to this code will be overwritten the next time we re-generate
+this code.
+
+If you are interested in using this code, despite the disclaimer above,
+fantastic! Please let the editor team know so that we can get a sense of the
+interest in it. Also, feel free to ask questions and make requests for
+additional functionality.