src/lib_spec.c: Enable the defun! function (fixes #2)

Now it is valid to define simple functions (still glitchy).
src/aklisp.c: Split stack and frame handler functions
src/compile.c: Execute 'main', instead of the whole IR
src/lexer.c: Use lower-case as the default
src/types.c: Global *_VALUEs should not be static
src/main.c: Follow the new naming conventions
src/lib.c: Add the 'print' function, fix some other