#19 Release notes updates for v0.1 + documentation improvements.
- Updated/extended released notes for v0.1. - Removed '(unreleased)' annotations in release notes. - Difficult to keep up-to-date. - Added more documentation cross-linking (ESCET to/from languages). - Using actual online URLs, which are now known. - Cross-linking information extended with what you'll find there. - Refer to website for development information. - Our tools are also available as plug-ins from an update site. - Some other small textual changes in documentation.