release 0.3.0 a complete rewrite

This differs from earlier versions in that
* whitespace is better preserved/removed around inserted/removed sexps
* there are more convenience commands
* doc-string is optionally preserved when updating sexp that support it
* some basic tests where added
* more flexible, better defaults
* order of arguments has changed a lot

The order of arguments is still subject to change.  Most importantly
the position of optional VALUE argument of save-sexp-save-* functions
might change because it has be the last argument and additional
optional arguments might be added in the future.