Keep colour theme on REPL reload

Now, the colour theme is no longer thrown out when using :r or :l.
Unification fix to avoid giving up on recoverable errors

If function names don't unify, we shouldn't try to univy arguments!
Otherwise, we can get unrecoverable unification failures if some
unrelated arguments later unify.

Fixes #465
Update version number
Merge pull request #486 from david-christiansen/color-repl

Keep colour theme on REPL reload
Merge pull request #487 from tauli/master

SimpleParser: improving performance so it is usefull for real world stuf...