combo: avoid divide by zero

This caused a quiet NaN, which then triggered OC_ASSERT in binaryEntropy.
Merge pull request #81 from linas/moses

combo: avoid divide by zero
initiated embodiment package for testing py-pln and fishgram
Merge pull request #82 from keyvan-m-sadeghi/master

initiated embodiment package for testing py-pln and fishgram
python atomspace is fixed by Jade, combination descriptors are vaguely defined, awaiting group discussion to decide how situations should be represented in the atomspace
Merge pull request #83 from keyvan-m-sadeghi/master

fixed python atomspace and more work on situation.py
Refactor combo's function-call system a little bit. Make the REPL load a file of procedures.
Make combo support lists inside procedures and cond's (but some complex cases still seem broken. It could use more refactoring)
Fix the PLEASURE code. Now it can generate all (reduced) combo trees containing specified operators.
Compile PLEASURE
Remove the special Embodiment Combo evaluator function (which handled unification, but that's not used anymore). It was a tacky hack, duplicating a lot of code
Refactor Combo evaluation so operators that can return a tree/vertex/either are all handled in the same function.
Clean up eval a bit more
Fix more combo bugs
Make PLEASURE support procedures
Change procedure evaluation so it won't use the terrible set_bindings system
Merge pull request #85 from ngeiswei/jade_moses_cherrypick_28fe32e198_to_4f5ad2f9ee

Jade moses cherrypick 28fe32e198 to 4f5ad2f9ee
the code now generates situations which can be used as a testbed for PLN and Fishgram
Merge pull request #86 from keyvan-m-sadeghi/master

Finished coding Situations and added __dict__ to AtomTypeList