nonfunctional tweaks to handling of '->'.
Use Dyna Boolean type instead of Python's bool. This requires redefining or
wrapping Python's comparsion (<=, ==), and logical operators (and, or,qq not).

move examples/lists into repl tests.
updated examples/force to use dyna lists
updated some other tests..
added test for dyna boolean operations.
minor cleanups
Merge branch 'master' of ssh://github.com/nwf/dyna

Conflicts:
	src/Dyna/Backend/Python/Backend.hs
	src/Dyna/Backend/Python/interpreter.py

Had to make a small change to pretty printing of @nwf's new representation of
true and false (they need to print as *lower case* true and false).
Merge branch 'master' of ssh://github.com/nwf/dyna