Version 1.2 release notice

[Tom Castle]

The latest version of EpochX (1.2) has just been released at
http://www.epochx.org.

The new release includes:
- XGE and XGR Evaluator/Executor interfaces replaced by the
simplified Interpreter interface.
- Support for evolving code in any programming language that provides
a ScriptEngine, using the new ScriptingInterpreter.
- New built-in models for all representations.
- Improved JavaDoc comments for the Common packages.
- Checking of grammars for infinite recursion or other invalid
structures.

This release includes some minor incompatibilities with previous
versions. In particular:
- use of Evaluators/Executors will need to be replaced with the
equivalent Interpreter.
- some built-in models have been replaced by more generalised models,
and their names have changed as appropriate.