v1.0

First major release, 18 years in the making 😄

• Replace custom parser with dparser (much easier to extend).
• Use sting interning, gives 2x speedup (thanks to @baziotis).
  We can now solve 8-queens in the pure calculus.
• Support [a,b,c] list notation in parser (syntactic sugar for a:b:c:Nil).
• Migrate from autotools to cmake.
• Replace readline by replxx (no external dependencies, windows support).
• Use same syntax in files and REPL (eg aliases can be defined in the REPL).
• Print \x.x as I (looks good since 1 reduces to I).
• Various polishing, cleanup and performance enhancements.
• Add simple tests, run them in gh-actions.